CVE-2026-64531Disclosure

HIGHCVSS 7.8 · HIGH

Exploitation observed; activity peaked at 12 mentions and remains active

Immediate actions

  • Patch affected systems immediately
  • Assume compromise if assets are exposed
  • Hunt for exploitation attempts and persistence artifacts
  • Increase monitoring for publicly documented tradecraft

Recommended action window: Immediate (within 24h)

NVD description

In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: reject oversized nested action attrs Open vSwitch stores generated flow actions as nlattrs, whose nla_len field is u16. Commit a1e64addf3ff ("net: openvswitch: remove misbehaving actions length check") allowed the total sw_flow_actions stream to grow beyond 64 KiB, which is valid, but also removed the last guard preventing a generated nested action attribute from exceeding U16_MAX. An oversized generated container can thus be closed with a truncated nla_len. A later dump or teardown then walks a structurally different stream than the one that was validated. In particular, an oversized nested CLONE/CT action may cause subsequent bytes in the generated stream to be interpreted as independent actions. Keep the larger total-action-stream behavior, but make nested action close reject generated containers that do not fit in nla_len, and return the error through all callers. For recursive SAMPLE, CLONE, DEC_TTL, and CHECK_PKT_LEN builders, trim resource-owning action-list tails in reverse construction order before discarding failed wrappers, so resources copied into the rejected tails are released before the wrappers are removed. Most failed outer wrappers are discarded by truncating actions_len after child resources have been released. CHECK_PKT_LEN also trims its parent after branch resources are gone. SET/TUNNEL close failures unwind their known tun_dst ownership directly, and SET_TO_MASKED has no external ownership and truncates on close failure.

7.8/ 10 priority

Sources & remediation

Weakness type (CWE)
CWE-190

Priority

HIGH

Exploitation

ACTIVE

PoC

YES

Patch

AVAILABLE

Momentum

DECLINING

Threat summary

  • Active exploitation appears in 2 classified signals
  • Public PoC and exploit tooling are both present
  • Patch or workaround signal is available
  • 38 mentions across 12 observed days

What's happening

  • Active exploitation reported across 2 signals
  • Exploit tool or code specified in 7 signals
  • PoC mentioned or linked in 16 signals
  • Patch or workaround mentioned in 14 signals
  • Technical details provided in 31 signals
  • Disclosure: 14 classified signals
  • General: 6 classified signals
  • Peaked 6d ago at 12 mentions (2026-08-05); latest day: 1
  • 38 total mentions across 12 days

Deep dive

Activity timeline38 mentions / 12d
036912Mentions · 2026-07-27: 2Mentions · 2026-07-28: 4Mentions · 2026-07-29: 2Mentions · 2026-08-03: 2Mentions · 2026-08-04: 2Mentions · 2026-08-05: 12Mentions · 2026-08-06: 7Mentions · 2026-08-07: 3Mentions · 2026-08-10: 1Mentions · 2026-08-13: 1Mentions · 2026-09-11: 1Mentions · 2026-09-21: 1PoC Mentioned / Linked · 2026-07-28: 1PoC Mentioned / Linked · 2026-08-03: 2PoC Mentioned / Linked · 2026-08-04: 2PoC Mentioned / Linked · 2026-08-05: 5PoC Mentioned / Linked · 2026-08-06: 3PoC Mentioned / Linked · 2026-08-07: 1PoC Mentioned / Linked · 2026-08-10: 1PoC Mentioned / Linked · 2026-09-11: 1Exploit Tool / Code · 2026-08-03: 1Exploit Tool / Code · 2026-08-04: 1Exploit Tool / Code · 2026-08-05: 3Exploit Tool / Code · 2026-08-06: 2Active Exploitation · 2026-07-28: 1Active Exploitation · 2026-07-29: 1Patch / Workaround · 2026-07-28: 1Patch / Workaround · 2026-07-29: 1Patch / Workaround · 2026-08-04: 1Patch / Workaround · 2026-08-05: 7Patch / Workaround · 2026-08-06: 2Patch / Workaround · 2026-08-07: 1Patch / Workaround · 2026-08-13: 1Technical Details · 2026-07-28: 2Technical Details · 2026-07-29: 2Technical Details · 2026-08-03: 2Technical Details · 2026-08-04: 2Technical Details · 2026-08-05: 11Technical Details · 2026-08-06: 6Technical Details · 2026-08-07: 2Technical Details · 2026-08-10: 1Technical Details · 2026-08-13: 1Technical Details · 2026-09-11: 1Technical Details · 2026-09-21: 107-2707-2807-2908-0308-0408-0508-0608-0708-1008-1309-1109-21
Signal classification6 categories
Disclosure
1436.8%
PoC
923.7%
General
615.8%
Patch
513.2%
Active Exploitation
25.3%
Exploit
25.3%
Referenced assets30 URLs
By indicator
Classification over time
DateTotalLabels
2026-07-272
Disclosure1General1
2026-07-284
Active Exploitation1General2Patch1
2026-07-292
Active Exploitation1General1
2026-08-032
Exploit1PoC1
2026-08-042
PoC2
2026-08-0512
Disclosure6Patch2PoC4
2026-08-067
Disclosure4Exploit1Patch1PoC1
2026-08-073
Disclosure1General1PoC1
2026-08-101
Disclosure1
2026-08-131
Patch1
2026-09-111
General1
2026-09-211
Disclosure1
Full discourse20 posts
  • The Hacker News@TheHackersNews
    PoC

    🛑 A Linux kernel root exploit is now public. The 13-year-old OVSwrap flaw (CVE-2026-64531) can let unprivileged local users gain root through Open vSwitch on affected systems. The public PoC includes offsets for roughly 800 x86-64 kernel builds. Patch or block the module: https://thehackernews.com/2026/08/new-ovswrap-linux-kernel-flaw-lets.html

    Post summary

    A public proof‑of‑concept for CVE-2026-64531 is released, supplying offsets for many kernel builds, and a patch or module block is recommended to mitigate the root‑privilege escalation flaw in Open vSwitch.

    3123647221659.1K
    2.4M followersView on X
  • elhacker.NET@elhackernet
    Disclosure

    Nueva vulnerabilidad de OVSwrap en Linux permite acceso root Se ha descubierto una nueva vulnerabilidad en el kernel de Linux, identificada como CVE-2026-64531 y denominada OVSwrap https://blog.elhacker.net/2026/08/nueva-vulnerabilidad-de-ovswrap-en.html

    Post summary

    A Spanish blog posts the discovery of CVE-2026-64531, a Linux kernel flaw that allows root access, without providing PoC, exploit code, or patch information.

    0282115288.5K
    142.4K followersView on X
  • Rıdvan Yağlı@ridvanyagli
    PoC

    🔴 Linux kernel'de OVSwrap (CVE-2026-64531) adıyla kritik bir LPE (Yerel Yetki Yükseltme) Açığı Keşfedildi + PoC Yayınlandı! Açık, openvswitch.ko modülünde. Generic netlink ile modül yükletilip nested action'lardaki 16-bit nla_len alanı taşırılıyor. Bu sayede kernel pointer sızıntısı ve kontrollü yazma ile credential'lar bozulup root shell açılıyor. Paylaşımlı hosting hizmeti sağlıyorsanız veya çok sayıda barındırma varsa sizin için tehlikeli olabilir. 👉 Hangi sistemleri etkiliyor? CloudLinux 9 -> el9_7 ve üzeri kernel'ler CloudLinux 10 -> el10_1 ve üzeri kernel'ler CloudLinux for Ubuntu 22.04 (tüm kernel'ler) RHEL 9 / AlmaLinux 9 / Rocky Linux 9 (el9_7+ kernel'ler) RHEL 10 / AlmaLinux 10 / Rocky Linux 10 (el10_1+ kernel'ler) Ubuntu 22.04 ve 24.04 (çoğu kernel track'i) Debian 12 ve 13 CentOS Stream 9 ve 10 Fedora 41, 42, 43, 44 Amazon Linux 2023 (bazı kernel track'leri) openSUSE Tumbleweed Not: openvswitch.ko modülü yoksa veya unprivileged userns kapalıysa risk düşük. 👉 Açığın olasılık kontrolü: ls /lib/modules/$(uname -r)/kernel/net/openvswitch/openvswitch.ko* 👉 Geçici önlem mitigasyon için kısa çözüm: echo 'install openvswitch /bin/false' > /etc/modprobe.d/ovswrap.conf Bu açık Upstream Linux kernel'de patch'lendi, ancak bazı işletim sistemleri için halen patch bekleniyor. Test repolardan kernel update denemeyi unutmayın. Write-up: https://heyitsas.im/posts/ovswrap PoC: https://github.com/manizada/OVSwrap

    Post summary

    The post announces CVE‑2026‑64531, a local privilege escalation in the openvswitch kernel module, provides exploitation details and a proof‑of‑concept, lists affected distros, and offers mitigation steps.

    020078476.0K
    2.4K followersView on X
  • yousukezan@yousukezan
    Disclosure

    Open vSwitch(OVS)のカーネルデータパスに存在する権限昇格脆弱性「OVSwrap」(CVE-2026-64531)が公開された。一般ユーザーでもroot権限を取得できる可能性があり、UbuntuやDebian、Fedoraなど多くのLinuxディストリビューションに影響する。修正版カーネルへの更新が推奨されている。 脆弱性は、Open vSwitchがユーザー空間から受け取るネットワークアクションをNetlink属性へ変換する際、16ビット長の制限を超えるネストしたアクションを適切に検証していなかったことに起因する。攻撃者が65,535バイトを超えるアクションを作成すると長さが小さな値へ折り返され、カーネルは攻撃者が制御するデータを新たな正規アクションとして誤って解析する。conntrackのラベルやタイムアウト名を攻撃者が制御できるため、メモリ操作を行わずに安定して悪用できるという。 攻撃には既存のOVSブリッジやスイッチデーモン、管理者権限は不要で、一般ユーザーがunshare -Urnでユーザー名前空間とネットワーク名前空間を作成し、その中でCAP_NET_ADMINを取得するだけで脆弱なコードパスへ到達できる。OVSモジュールは多くの環境で必要時に自動読み込みされるため、OVSを意図的に利用していないシステムでも影響を受ける可能性がある。問題は約13年間存在していたが、2025年にサイズ制限が撤廃された変更により悪用可能となった。修正は5.15.212、6.1.178、6.6.145、6.12.97、6.18.40、7.1.5などへ取り込まれている。 https://cybersecuritynews.com/ovswrap-linux-vulnerability/

    Post summary

    CVE‑2026‑64531 is a privilege‑escalation vulnerability in Open vSwitch’s kernel datapath, exploitable by general users crafting oversized Netlink actions; recent kernels have been patched and updates are recommended.

    01101431.7K
    16.0K followersView on X
  • Ruben Groenewoud@RFGroenewoud
    PoC

    New (working) Linux LPE: OVSwrap (CVE-2026-64531). blog: https://heyitsas.im/posts/ovswrap/ poc: https://github.com/manizada/OVSwrap Existing Elastic Defend prevention & detection coverage https://t.co/KlNyHgFGU8

    Post summary

    A working Linux local privilege escalation bug (OVSwrap, CVE‑2026‑64531) has been disclosed with a PoC available on GitHub, and existing Elastic Defend coverage is referenced.

    0601621.1K
    878 followersView on X
  • st8le̤̤̤̤̤̤̤̤̤̤ss@st8less
    PoC

    OVSwrap | CVE-2026-64531 PoC Linux LPE to root from unprivledged user. you don't need OVS running or even loaded. Resolving the genetlink family by name autoloads the module. Not universal but very broad vulnerable distro list. Writeup: https://heyitsas.im/posts/ovswrap/ PoC: https://github.com/manizada/OVSwrap

    Post summary

    A PoC for CVE‑2026‑64531 is available, demonstrating a Linux local privilege‑escalation via genetlink autoload, with detailed writeup and GitHub repository provided.

    01075729
    661 followersView on X
  • Open Source Security mailing list@oss_security
    Disclosure

    CVE-2026-64531,OVSwrap: Linux kernel: Local root vuln in Open vSwitch datapath https://www.openwall.com/lists/oss-security/2026/07/28/8 where: - OVS kernel datapath and conntrack/FTP-helper support are present, and - unprivileged user/network namespaces are enabled, or the attacker otherwise has CAP_NET_ADMIN

    Post summary

    The brief notification announces CVE-2026-64531, a local root flaw in Open vSwitch’s kernel datapath, outlining the conditions that enable exploitation but providing no patch, tool, or evidence of active attacks.

    010801.3K
    4.7K followersView on X
  • dbugs@ptdbugs
    Exploit

    A PoC/exploit has been discovered for vulnerability CVE-2026-64531 PT ID: PT-2026-64855 Vendor: Linux Product: Linux Description: Open vSwitch stores generated flow actions as nlattrs, which use a nla len field of type u16. A previous change allowed the total sw flow actions stream to exceed 64 KiB but removed the protection preventing a generated nested action attribute from exceeding U16 MAX. This allows an oversized generated container to be closed with a truncated nla len. Consequently, a subsequent dump or teardown process may traverse a structurally different stream than the one originally validated. Specifically, an oversized nested CLONE or CT action can lead to subsequent bytes in the generated stream being incorrectly interpreted as independent actions. References: • https://dbugs.ptsecurity.com/vulnerability/PT-2026-64855 • https://github.com/hackspeak/ovswrap-poc #dbugs_vuln

    Post summary

    A PoC and functional exploit for CVE‑2026‑64531 are disclosed, accompanied by technical details and a GitHub repository, but no evidence of active exploitation or vendor patch is mentioned.

    00072789
    3.6K followersView on X
  • NanoVMs@nanovms
    General

    oh look unpriv user namespaces strike again CVE-2026-64531 https://t.co/8wEqdYSjGI

    Post summary

    The tweet references CVE‑2026‑64531 for unprivileged user namespaces but provides no exploit, PoC, active‑exploitation, patch, or false‑positive details.

    01070549
    2.3K followersView on X
  • DFIR Radar@DFIR_Radar
    General

    Elastic Security Labs maps a durable, outcome-oriented Linux LPE detection framework against 11 public 2026 PoCs, covering page-cache corruption, namespace abuse, trusted-helper theft, and SUID misconfiguration without relying on per-CVE rules. Key findings: - Seven of 13 tracked 2026 Linux LPEs share a copy-on-write page-cache corruption primitive: Copy Fail (CVE-2026-31431), DirtyFrag (CVE-2026-43284/43500), Fragnesia (CVE-2026-46300), DirtyDecrypt (CVE-2026-31635), pedit COW (CVE-2026-46331), DirtyClone (CVE-2026-43503), and RefluXFS. The kernel trigger varies across AF_ALG, ESP/RxRPC, act_pedit, and skb helpers, but every exploit still ends the same way: a SUID helper or interpreter runs with effective uid 0. Qualys and others used LLM-assisted workflows to discover several of these, accelerating the per-bug-class pace. - The framework detects in two layers. Layer one is outcome-oriented: exec from a writable path (/tmp, /dev/shm, /var/tmp, /home, /run/user) followed by a uid_change to 0, correlated by parent entity ID within a short window. Layer two adds per-class signals: AF_ALG socket bursts plus splice for Copy Fail; unshare(CLONE_NEWUSER) preceding a root transition for CIFSwitch (CVE-2026-46243) and OVSwrap (CVE-2026-64531); busctl --system calls for ptrace_may_dream; and shadow-read alerts for chage_pwn (CVE-2026-46333). - CVE-2026-46333 (exit-time FD theft via pidfd_getfd) is worth special attention. #DFIR_Radar

    Post summary

    Elastic Security Labs unveiled a detection framework that maps 11 public 2026 Linux privilege‑escalation PoCs, providing technical details for each exploit while noting no active exploitation or patch information.

    20100268
    1.9K followersView on X
  • Sam Stepanyan@securestep9
    Disclosure

    #Linux: a 13-year-old Linux kernel flaw dubbed #OVSWrap lets local users gain root privileges on most Linux distributions. CVE-2026-64531 vulnerability is in the Linux kernel’s Open vSwitch datapath: #PrivilegeEscalation 👇 https://securityaffairs.com/196657/hacking/ovswrap-13-year-old-linux-kernel-flaw-lets-local-users-become-root.html

    Post summary

    The tweet announces the discovery of CVE-2026-64531, a long‑existing kernel flaw that lets local users gain root privileges on many Linux distributions, without providing PoC, patch, or exploitation evidence.

    00030348
    7.4K followersView on X
  • protect_cyber_sec@AmirHossein_sec
    Disclosure

    آسیب پذیری جدیدی با کد شناسایی CVE-2026-64531 از نوع privilege escalation برای کرنل لینوکس منتشر شده است. کاربران با استفاده از این آسیب پذیری ، می توانند سطح دسترسی خود را به یوزر root ارتقا دهند ، برای پیشگیری و مقابله به روز رسانی نمایید. https://t.co/xhtLO70GOa

    Post summary

    A new Linux kernel privilege‑escalation vulnerability (CVE‑2026‑64531) has been announced, and users are advised to apply updates to mitigate the risk.

    00021252
    207 followersView on X
  • Adam@seoscottsdale
    General

    https://x.com/seoscottsdale/status/2085479543054487664?s=46 @grok Please analyze the thread above (or the quoted thread) for accuracy and source quality. Focus on: - Technical accuracy of all CVE descriptions, CVSS scores, exploitation status, affected versions, patch availability, and timelines - Correctness of “why it matters” implications (especially supply chain, verification/provenance, multi-agent systems, and SMB practicality) - Accuracy of research paper summaries and their claimed implications (Trojan Horse effects, verification topologies, etc.) - Quality and traceability of sources cited - Any claims that are unsourced, overstated, or could benefit from primary source links Use tools to verify against CISA KEV, NVD, vendor advisories (Microsoft, Palo Alto, Widget Factory, etc.), arXiv, Unit 42, and researcher disclosures where relevant. **Additional requirement (new):** Search for and surface the strongest primary links and references that should have been (or can still be) attached to the original posts. Specifically locate and provide: - Direct CISA KEV catalog entry / addition announcement for the three 4 Aug 2026 CVEs - Unit 42 full write-up on ChainDrop - Elastic Security Labs analysis of the CHAINDROP / Shai-Hulud variant - Veeam KB4892 (Vulnerabilities Resolved in Veeam ONE 13.1) - Official Apache Tomcat security pages / mailing-list advisory for CVE-2026-34486 - oss-sec disclosure + public PoC repository for OVSwrap (CVE-2026-64531) Include these primary URLs in the Source Verification and Suggested Improvements sections so the thread can be strengthened with direct, authoritative citations. Output in this exact structure: 1. Overall Accuracy Assessment (High / Medium / Low + one-sentence summary) 2. Specific Flags or Corrections (Bullet list — only include items that need attention) 3. Source Verification (Which claims are well-sourced vs. would benefit from stronger primary links) → Explicitly list the primary URLs found above 4. Strengths (What works well technically or for the audience) 5. Suggested Improvements (Concise, high-signal recommendations for clarity, precision, or actionability) → Include concrete primary-link suggestions Be concise, neutral, and technical. Treat this as a verification request for a technically sophisticated audience focused on secure multi-agent systems and practical defenses.

    Post summary

    The text lacks concrete information on the CVE, making it difficult to assess technical accuracy or provide actionable insights.

    10010132
    12.4K followersView on X
  • OS開発者@hacker_infra
    General

    https://access.redhat.com/security/cve/cve-2026-64531 コードが2025年からはいっているのに RHEL6が影響するわけねーだろう。 それにLPEが公開されているから importantに変更になるだろ。 こういう一時情報を間違えると悲惨だぞ Red hat大丈夫か・・・・。 RHEL8コードパスが存在しないからいいけど

    Post summary

    The excerpt speculates on the impact and severity of CVE-2026‑64531 but provides no concrete evidence of exploitation, patches, or debunking.

    00011277
    2.9K followersView on X
  • OS開発者@hacker_infra
    Active Exploitation

    新しいLPE CVE-2026-64531、Red hat cve databaseがないから、 メールで通報。影響を受けるのはubuntu22以上とAlma9以上でエクスプロイトが成功している。 緩和策は printf 'blacklist openvswitch\ninstall openvswitch /bin/false\n' | sudo tee /etc/modprobe.d/disable-openvswitch.conf >/dev/null && sudo modprobe -r openvswitch 名前空間の無効化 https://www.openwall.com/lists/oss-security/2026/07/28/8

    Post summary

    CVE-2026-64531 is a local privilege escalation vulnerability affecting Ubuntu 22+ and Alma9+; it has been actively exploited, and a mitigation script is provided.

    00101460
    2.9K followersView on X
  • iototsecnews@iototsecnews
    Patch

    OVSwrap Open vSwitch の脆弱性 CVE-2026-64531 が FIX:Linux root 権限奪取の恐れ https://iototsecnews.jp/2026/08/05/ovswrap-open-vswitch-flaw-lets-unprivileged-linux-users-gain-root-access/ Linux カーネルの Open vSwitch (OVS) 実装における、整数ラップアラウンドの欠陥 CVE-2026-64531 を悪用する権限を持たないユーザーにより、最高権限である root 権限が奪取される恐れがあります。この影響を防ぐため、修正が含まれる最新のカーネルへのバージョンアップを実施する必要があります。更新が困難な状況では、不要な OVS モジュールのアンロードおよびブラックリスト登録を行い、非特権ユーザー名前空間の作成権限を制限することで被害を回避できます。製品を安全に利用するためにも、迅速な環境整備と設定の見直しが推奨されます。 #CVE202664531 #OpenvSwitch #OVSwrap #Vulnerability

    Post summary

    The text reports CVE‑2026‑64531, an integer wrap‑around flaw in Open vSwitch that could lead to root‑privilege escalation, and it calls for kernel upgrades and specific mitigations.

    01000160
    507 followersView on X
  • DFIR Radar@DFIR_Radar
    PoC

    CVE-2026-64531 (CVSS 7.8) is a 13-year-old Linux kernel Open vSwitch LPE, made reachable by a March 2025 cap removal. A public PoC targets ~800 kernel builds across Debian, Ubuntu, Fedora, and more. Patch now or block the module with modprobe.d. #DFIR_Radar https://t.co/EXYKGUN6bI

    Post summary

    The tweet highlights CVE-2026-64531, noting a public PoC targeting ~800 Linux kernel builds and urging users to patch or block the affected module.

    10000211
    1.8K followersView on X
  • Halil Deniz@denizhalilT
    Disclosure

    🚨 New Security Analysis! Deep dive into CVE-2026-64531 (OVSwrap), a critical Linux kernel Local Privilege Escalation flaw in Open vSwitch. Learn how Netlink integer wrapping leads to root access. https://denizhalil.com/2026/08/06/cve-2026-64531-ovswrap-linux-kernel-lpe/ #CVE202664531 #LinuxKernel #CyberSecurity https://t.co/BI4lSj7IzG

    Post summary

    The tweet offers a detailed analysis of CVE‑2026‑64531, explaining a critical LPE bug in Open vSwitch due to Netlink integer wrapping, but does not discuss patches, active exploitation, or PoC code.

    0001077
    32 followersView on X
  • CyberTLDR@CyberTLDR
    Exploit

    1/3 A new Linux kernel flaw hands local users root, and a public exploit already ships records for around 800 kernel builds. OVSwrap (CVE-2026-64531) sits in the Open vSwitch datapath on many default distros. Are you exposed? #CyberSecurity #InfoSec #Linux #CVE https://t.co/ksAMoOUp66

    Post summary

    The tweet announces that CVE‑2026‑64531, a Linux kernel flaw via Open vSwitch, allows local privilege escalation to root and that a public exploit is already available.

    1000058
    40 followersView on X
  • Machina Record@MachinaRecord
    Disclosure

    ⚠️Linuxカーネルの脆弱性「OVSwrap」:Open vSwitch経由でローカルユーザーがroot権限を取得可能に(CVE-2026-64531) 🇨🇭スイス連邦通信技術局がハッキングされる SharePointの脆弱性を悪用 〜サイバーアラート8月6日〜 https://codebook.machinarecord.com/threatreport/silobreaker-cyber-alert/47047/

    Post summary

    A cyber alert announces the Linux kernel vulnerability CVE-2026‑64531 (OVSwrap), which allows local users to gain root privileges via Open vSwitch, and briefly references a Swiss Federal Communications Agency hack involving SharePoint.

    00010299
    1.3K followersView on X

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