CVE-2026-23553General(xen / xen)

LOWCVSS 2.9 · LOW

Signal is active with 1 mentions in latest observed window

Immediate actions

Patch xen xen systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

In the context switch logic Xen attempts to skip an IBPB in the case of a vCPU returning to a CPU on which it was the previous vCPU to run. While safe for Xen's isolation between vCPUs, this prevents the guest kernel correctly isolating between tasks. Consider: 1) vCPU runs on CPU A, running task 1. 2) vCPU moves to CPU B, idle gets scheduled on A. Xen skips IBPB. 3) On CPU B, guest kernel switches from task 1 to 2, issuing IBPB. 4) vCPU moves back to CPU A. Xen skips IBPB again. Now, task 2 is running on CPU A with task 1's training still in the BTB.

xen CVEs Back to dashboard

0.5/ 10 priority

Sources & remediation

Patch / fix

Weakness type (CWE)

CWE-665CWE-693

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.

Threat summary

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

What's happening

Patch or workaround mentioned in 3 signals
Technical details provided in 5 signals
General: 3 classified signals
Disclosure: 1 classified signal
Peaked 2d ago at 3 mentions (2026-01-27); latest day: 1
7 total mentions across 3 days

Affected systems

Vendors

xen

Products

xen

Deep dive

Activity timeline7 mentions / 3d

Signal classification3 categories

General

342.9%

Patch

342.9%

Disclosure

114.3%

Referenced assets7 URLs

By indicator

Classification over time

Date	Total	Labels

2026-01-27	3	General2Patch1
2026-01-28	3	Disclosure1General1Patch1
2026-01-30	1	Patch1

Full discourse7 posts

Open Source Security mailing list@oss_security254d
Disclosure
3 new Xen Security Advisories https://www.openwall.com/lists/oss-security/2026/01/27/ 477 CVE-2025-58150 x86: buffer overrun with shadow paging + tracing 478 CVE-2025-58151 varstored: TOCTOU issues with mapped guest memory 479 CVE-2026-23553 x86: incomplete IBPB for vCPU isolation
Post summary
Three new Xen security advisories are released, outlining buffer overrun, TOCTOU, and incomplete IBPB vulnerabilities, without mentioning PoC, exploits, or patches.
01073739
4.4K followersView on X
Autumn Good@autumn_good_35255d
Patch
CITRIX | Support XenServer Security Update for CVE-2025-58151 and CVE-2026-23553 https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX695997&articleURL=XenServer_Security_Update_for_CVE_2025_58151_and_CVE_2026_23553
Post summary
Citrix publishes a security update for XenServer addressing CVE‑2025‑58151 and CVE‑2026‑23553; the post offers no PoC, exploit code, active exploitation details, or technical vulnerability specifics.
01020397
6.7K followersView on X
Autumn Good@autumn_good_35255d
General
CVE-2026-23553 x86: incomplete IBPB for vCPU isolation CVE-2025-58151 varstored: TOCTOU issues with mapped guest memory CVE-2025-58150 x86: buffer overrun with shadow paging + tracing Xen Security Advisories https://xenbits.xen.org/xsa/
Post summary
The text lists three Xen-related CVEs with short technical notes and a link to the Xen Security Advisories page, but it provides no PoC, exploit code, patch details, or evidence of active attacks.
10000376
6.7K followersView on X
Ferramentas Linux@Cezar_H_Linux252d
Patch
🚨 Attention System Administrators & DevOps Teams! 🚨 Mageia has released a critical security update, MGASA-2026-0026, patching two high-severity Xen hypervisor vulnerabilities (CVE-2025-58150 & CVE-2026-23553). Read more: 👉 https://tinyurl.com/4uc6es63 #Security https://t.co/dY9T33dkPF
Post summary
Mageia announced a critical update (MGASA‑2026‑0026) that patches two high‑severity Xen hypervisor CVEs (CVE‑2025‑58150, CVE‑2026‑23553).
00000101
1.3K followersView on X
Ferramentas Linux@Cezar_H_Linux254d
Patch
URGENT: #openSUSE Leap 15.6 users must patch Xen hypervisor vulnerabilities CVE-2025-58150 (buffer overrun) and CVE-2026-23553 (incomplete IBPB). Read more: 👉 https://tinyurl.com/3yvpza8s #Security https://t.co/IgMwGkuP5z
Post summary
The tweet is a patch urgency advisory for openSUSE Leap 15.6 users, highlighting the need to update Xen hypervisor for CVE-2025-58150 (buffer overrun) and CVE-2026-23553 (incomplete IBPB).
0000047
1.3K followersView on X
CVE@CVEnew254d
General
CVE-2026-23553 In the context switch logic Xen attempts to skip an IBPB in the case of a vCPU returning to a CPU on which it was the previous vCPU to run. While safe for Xen's isola… https://www.cve.org/CVERecord?id=CVE-2026-23553
Post summary
The post references CVE-2026-23553 and gives a brief technical description of the vulnerability in Xen’s context‑switch logic, but does not provide evidence of a PoC, exploit, patch or active exploitation.
00000147
56.5K followersView on X
Vulmon Vulnerability Feed@VulmonFeeds255d
General
CVE-2026-23553 Xen Security Advisory 479 v2 (CVE-2026-23553) - x86 https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-23553
Post summary
The advisory references CVE-2026-23553 but offers no detailed information about exploitation, patching, or technical specifics in the provided text.
0000042
4.0K followersView on X

CPE platform detail1 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

1 of 1 entries

Part	Vendor	Product	Version	Target SW	Target HW
OS	xen	xen	-	-	x86

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What researchers are saying

CVE-2026-23553

Open Source Security mailing list@oss_securityDisclosure

Three new Xen security advisories are released, outlining buffer overrun, TOCTOU, and incomplete IBPB vulnerabilities, without mentioning PoC, exploits, or patches.

Autumn Good@autumn_good_35Patch

Citrix publishes a security update for XenServer addressing CVE‑2025‑58151 and CVE‑2026‑23553; the post offers no PoC, exploit code, active exploitation details, or technical vulnerability specifics.

Autumn Good@autumn_good_35General

The text lists three Xen-related CVEs with short technical notes and a link to the Xen Security Advisories page, but it provides no PoC, exploit code, patch details, or evidence of active attacks.

Ferramentas Linux@Cezar_H_LinuxPatch

Mageia announced a critical update (MGASA‑2026‑0026) that patches two high‑severity Xen hypervisor CVEs (CVE‑2025‑58150, CVE‑2026‑23553).

Ferramentas Linux@Cezar_H_LinuxPatch

The tweet is a patch urgency advisory for openSUSE Leap 15.6 users, highlighting the need to update Xen hypervisor for CVE-2025-58150 (buffer overrun) and CVE-2026-23553 (incomplete IBPB).

CVE@CVEnewGeneral

The post references CVE-2026-23553 and gives a brief technical description of the vulnerability in Xen’s context‑switch logic, but does not provide evidence of a PoC, exploit, patch or active exploitation.

Vulmon Vulnerability Feed@VulmonFeedsGeneral

The advisory references CVE-2026-23553 but offers no detailed information about exploitation, patching, or technical specifics in the provided text.