Is there a patch available for CVE-2026-99256?

Yes, a patch is available for CVE-2026-99256. Update the affected software to the latest version immediately.

Linux CVE-2026-99256

EUVD-2026-115767

2026-11-03 Linux

GHSA-pr5p-x5rg-2942

Information Disclosure Linux

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Awaiting Data No severity or threat signals available yet. Label will update when CVSS score is published or threat intelligence arrives.

Patch available

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AnalysisCVE.org

In the Linux kernel, the following vulnerability has been resolved:

dm cache: fix issue with background work locking

dm cache used a rw_semaphore for background_work_lock. Write locks on rw_semaphores have strict owner semantics, but there was no guarantee that the process that locked background_work_lock was the same process that unlocked it. This can be easily seen using a kernel compiled with CONFIG_DEBUG_RWSEMS. Given a dm cache device <cache>, run: 'dmsetup suspend <cache> && dmsetup resume <cache>'. This will trigger a kernel warning:

DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE))

triggered by cache_resume(). To fix this, switch from a rw_semaphore to a spinlock and a wait queue. dm cache already has a wait queue and associated counter, migration_wait and nr_allocated_migrations, that was getting woken up when background work was getting completed, but wasn't actually used by anything. This is replaced by the background_work queue and counter.

Affected VersionsENISA

Linux b29d4986d0da1a27cd35917cdb433672f5c95d7f <2f2cfa16dd0f4179bb988139dd37d00a42324f6c

Linux b29d4986d0da1a27cd35917cdb433672f5c95d7f <bc9781c0247de107876f32929f1637db93a42b34

Linux b29d4986d0da1a27cd35917cdb433672f5c95d7f <0c7a8cad7c96012a9157a189649e569d0390f384

Linux patch: 6.1.191

Linux patch: 6.6.161

Linux 4.12

Linux patch: 6.12.115

Linux patch: 7.2.13

Linux b29d4986d0da1a27cd35917cdb433672f5c95d7f <8433fd005c25fd127021f67c9144a879fb585572

Linux b29d4986d0da1a27cd35917cdb433672f5c95d7f <73df2ff409f3db95029982fe3656329568e3715d

Linux patch: 6.18.59

Linux patch: 5.10.273

Linux b29d4986d0da1a27cd35917cdb433672f5c95d7f <f5db935d257023c3ef410bd39163b949b0e5a55d

Linux b29d4986d0da1a27cd35917cdb433672f5c95d7f <104f09e02038b0fc6bbb718b3976af029e15c1d0

Linux patch: 5.15.224

Linux patch: 7.3

Linux b29d4986d0da1a27cd35917cdb433672f5c95d7f <6290507ecc0dd6dd40759729cbbbd49b1d2a63c4

Linux patch: 0

Affected Packages

euvd linux no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

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Exploit and PoC references, threat intelligence from 22 sources

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Lifecycle Timeline

Patch available

Nov 03, 2026 - 12:16 EUVD

CVE Published

Nov 03, 2026 - 11:25 cve.org

UNKNOWN (no severity yet)

Threat Intelligence Overview

Data Quality

1 sources

Confidence: Low

EUVD

CVE.org

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity Not scored yet

CISA KEV No

Public POC No

EPSS N/A

Patch available Yes

Active threat No

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

Awaiting Data No severity or threat signals available yet. Label will update when CVSS score is published or threat intelligence arrives.

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.