VulnSocial

CVE-2026-66035Patch(libssh2 / libssh2)

LOWCVSS 7.7 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch libssh2 libssh2 systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

libssh2 through 1.11.1, fixed in commit 42e33d8, contains a pre-authentication heap buffer overflow vulnerability that allows a malicious SSH server to corrupt heap metadata in any connecting client by sending a packet with a packet_length smaller than the cipher's block size during Encrypt-then-MAC cipher negotiation. In the fullpacket() function in src/transport.c, the ETM path allocates a buffer of packet_length bytes but copies blocksize minus one bytes via memcpy, causing an overflow that on 32-bit glibc writes attacker-controlled bytes into an adjacent chunk's SIZE field, enabling tcache bin confusion, overlapping live objects, and function pointer overwrite during the session handshake before authentication.

libssh2 CVEsBack to dashboard
0.5/ 10 priority

Sources & remediation

Patch / fix
Weakness type (CWE)
CWE-122

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • libssh2

Threat summary

  • Patch or workaround signal is available
  • 3 mentions across 3 observed days
  • Momentum state: stable

What's happening

  • Patch or workaround mentioned in 2 signals
  • Technical details provided in 2 signals
  • Disclosure: 1 classified signal
  • Peaked 2d ago at 1 mentions (2026-07-28); latest day: 1
  • 3 total mentions across 3 days

Affected systems

Vendors
libssh2
Products
libssh2

Deep dive

Activity timeline3 mentions / 3d
00111Mentions · 2026-07-28: 1Mentions · 2026-08-05: 1Mentions · 2026-10-15: 1Patch / Workaround · 2026-07-28: 1Patch / Workaround · 2026-08-05: 1Technical Details · 2026-07-28: 1Technical Details · 2026-08-05: 107-2808-0510-15
Signal classification2 categories
Patch
266.7%
Disclosure
133.3%
Referenced assets1 URL
Classification over time
DateTotalLabels
2026-07-281
Patch1
2026-08-051
Patch1
2026-10-151
Disclosure1
Full discourse3 posts
  • iototsecnews@iototsecnews
    Patch

    libssh2 の脆弱性 CVE-2026-66032／66033／66034／66035 が FIX：悪意の SSH サーバによるクライアント破壊 https://iototsecnews.jp/2026/07/28/libssh2-vulnerabilities-allow-a-malicious-ssh-server-to-corrupt-client-memory/ libssh2 の脆弱性 CVE-2026-66032／CVE-2026-66033／CVE-2026-66034／CVE-2026-66035 は、接続時のデータ検証やメモリ管理の不備に起因するものです。悪意の送信元との通信により内部の処理が乱され、プログラムの停止や意図しない動作などが引き起こされる恐れがあります。システムを安全に利用するためにも、対策が施された修正版ライブラリへの更新を速やかに実施してください。組み込み型のプログラムを利用している場合には、個別でのアップデート対応が必要になる点にも注意が必要です。 #CVE202666032 #CVE202666033 #CVE202666034 #CVE202666035 #libssh2 #Vulnerability

    Post summary

    The article announces that the libssh2 CVEs 2026‑66032‑66035 cause memory corruption via malicious SSH servers and urges users to update to the patched library immediately.

    02000159
    506 followersView on X
  • GCP Weekly@gcpweekly
    Disclosure

    This addresses the following vulnerabilities: CVE-2026-35189 CVE-2026-35191 CVE-2026-42772 CVE-2026-5450 CVE-2026-54872 CVE-2026-54873 CVE-2026-54875 CVE-2026-58050 CVE-2026-58051 CVE-2026-5928 CVE-2026-66032 CVE-2026-66033 CVE-2026-66034 CVE-2026-66035 CVE-2026-72897 5/16

    Post summary

    The text is a brief listing of multiple CVE identifiers with a date, providing no additional context, technical details, or remediation information.

    1000029
    1.8K followersView on X
  • Rıdvan Yağlı@ridvanyagli
    Patch

    🔴 libssh2'de keşfedilen dört kritik güvenlik açığı (CVE-2026-66032, CVE-2026-66033, CVE-2026-66034 ve CVE-2026-66035), kötü niyetli bir SSH/SFTP sunucusunun istemci uygulamalarında bellek bozulmasına, uygulamanın çökmesine ve bazı senaryolarda potansiyel uzaktan kod çalıştırmaya neden olabilmesine yol açıyor. Etkilenen sürümler: libssh2 1.11.1 ve öncesi. Kullanıcıların ve sistem yöneticilerinin, libssh2'yi veya bu kütüphaneyi kullanan uygulamaları güncel sürüme yükseltmeleri önerilir.

    Post summary

    Four critical vulnerabilities in libssh2 can lead to memory corruption, crashes, and potential remote code execution; users are advised to upgrade beyond version 1.11.1.

    0000084
    1.3K followersView on X
CPE platform detail1 entries

1 of 1 entries

PartVendorProductVersionTarget SWTarget HW
Applibssh2libssh2---

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