Linux Kernel: Race Condition (CVE-2026-99136)
Published Last modified Sources: Debian, Msrc Update Guide, CVE.org, BSI
What is affected, what to do
In the Linux kernel, the following vulnerability has been resolved: dm-crypt: fix a tiny race condition in crypt_dec_pending crypt_dec_pending reads io->error before calling atomic_dec_and_test. Another context, for example crypt_endio called from an interrupt, may set io->error and drop its reference between the read and the decrement. crypt_dec_pending then drops the last reference and completes the bio with the stale status - so a read that failed and was never decrypted, or a write that failed, is reported as successful.
The available sources name no fixed version. Check the vendor guidance in the references below.
Conflicting version data — version display is hidden until the data is resolved.
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Metrics
7.1
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v3
7.1
CVSS v3
Severity High on the scale from 0 to 10.
Source: Debian, Msrc Update Guide, CVE.org, BSI
0.1 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 2.0
Show all metrics
- Severity
- High
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 65.53 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 7.1 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 7.1
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 0.1 %
- Low — model estimates < 1% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 2.0
- Low — this CVE sits in the lower 10% of all CVEs scored today.
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
In the Linux kernel, the following vulnerability has been resolved: dm-crypt: fix a tiny race condition in crypt_dec_pending crypt_dec_pending reads io->error before calling atomic_dec_and_test. Another context, for example crypt_endio called from an interrupt, may set io->error and drop its reference between the read and the decrement. crypt_dec_pending then drops the last reference and completes the bio with the stale status - so a read that failed and was never decrypted, or a write that failed, is reported as successful. The read was placed before the decrement by commit b35f8caa0890 ("dm crypt: wait for endio to complete before destruction"), because that commit freed dm_crypt_io before calling bio_endio. This is no longer the case, dm_crypt_io lives in the per-bio data now. Read io->error after atomic_dec_and_test instead. atomic_dec_and_test is fully ordered, so no additional barrier is needed.
Source: Debian Security Advisories, Microsoft Security Update Guide, cvelistv5, NVD (NIST), BSI WID Portal, BSI CSAF
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Linux | Linux |
|
|
Vendors and products
Affected operating systems
| Linux | debian | linux | trixie |
References & sources
- git.kernel.orgstable/c/148845aa1921d95ef5dc851c76e6a284f6657df6
- git.kernel.orgstable/c/4f16bb982b27b9f5a15301f622c318001fe521f8
- git.kernel.orgstable/c/ac5d887ab93592fc5e3605fe30c1d8d232d609b3
- git.kernel.orgstable/c/056bf8322e39a48026df352d6227ec03dd8cd032
- git.kernel.orgstable/c/445a6883f46d3ab1ff545199a8cc1d5834936d3f
- git.kernel.orgstable/c/6ac8546df1f8a2b1ca7f6d67c269057a99fbbf8c
- git.kernel.orgstable/c/6f82e86471c92fd874f2630c9a6af887f4ed1a77
- git.kernel.orgstable/c/d9d7069bb79139271b54dc477f07e242c445de6b
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
Record modifiedLinux
CVSS V3.1: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Show the original change
Individual changes of this event as published by NVD Type Action Before After CVSS added —AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HSource identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Record modifiedLinux
New references:- https://git.kernel.org/stable/c/056bf8322e39a48026df352d6227ec03dd8cd032
- https://git.kernel.org/stable/c/445a6883f46d3ab1ff545199a8cc1d5834936d3f
- https://git.kernel.org/stable/c/6ac8546df1f8a2b1ca7f6d67c269057a99fbbf8c
- https://git.kernel.org/stable/c/6f82e86471c92fd874f2630c9a6af887f4ed1a77
and 1 more reference
Show 6 original changes
Individual changes of this event as published by NVD Type Action Before After Affected versions (publisher) added —Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/99xxx/CVE-2026-99136.json">CVE-2026-99136</a>Reference added —https://git.kernel.org/stable/c/056bf8322e39a48026df352d6227ec03dd8cd032Reference added —https://git.kernel.org/stable/c/445a6883f46d3ab1ff545199a8cc1d5834936d3fReference added —https://git.kernel.org/stable/c/6ac8546df1f8a2b1ca7f6d67c269057a99fbbf8cReference added —https://git.kernel.org/stable/c/6f82e86471c92fd874f2630c9a6af887f4ed1a77Reference added —https://git.kernel.org/stable/c/d9d7069bb79139271b54dc477f07e242c445de6bSource identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
ReceivedLinux
Description added or changed
Show 5 original changes
Individual changes of this event as published by NVD Type Action Before After Description added —In the Linux kernel, the following vulnerability has been resolved: dm-crypt: fix a tiny race condition in crypt_dec_pending crypt_dec_pending reads io->error before calling atomic_dec_and_test. Another context, for example crypt_endio called from an interrupt, may set io->error and drop its reference between the read and the decrement. crypt_dec_pending then drops the last reference and completes the bio with the stale status - so a read that failed and was never decrypted, or a write that failed, is reported as successful. The read was placed before the decrement by commit b35f8caa0890 ("dm crypt: wait for endio to complete before destruction"), because that commit freed dm_crypt_io before calling bio_endio. This is no longer the case, dm_crypt_io lives in the per-bio data now. Read io->error after atomic_dec_and_test instead. atomic_dec_and_test is fully ordered, so no additional barrier is needed.Affected versions (publisher) added —New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/99xxx/CVE-2026-99136.json">CVE-2026-99136</a>Reference added —https://git.kernel.org/stable/c/148845aa1921d95ef5dc851c76e6a284f6657df6Reference added —https://git.kernel.org/stable/c/4f16bb982b27b9f5a15301f622c318001fe521f8Reference added —https://git.kernel.org/stable/c/ac5d887ab93592fc5e3605fe30c1d8d232d609b3Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
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<a href="https://intel.neosec.eu/en/cve/CVE-2026-99136"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-99136.svg?lang=en" alt="CVE-2026-99136 – NEOSEC Intel" height="20"></a>