[KEV] Vulnerability in Linux redhat (CVE-2026-31431)
Summary
vulnerability in Linux redhat (CVE-2026-31431). Successful exploitation can lead to full system takeover. Listed in CISA KEV — actively exploited.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
crypto: algif_aead - Revert to operating out-of-place
This mostly reverts commit 72548b093ee3 except for the copying of
the associated data.
There is no benefit in operating in-place in algif_aead since the
source and destination come from different mappings. Get rid of
all the complexity added for in-place operation and just copy the
AD directly.
Source: CISA Known Exploited Vulnerabilities NVD GitHub Advisory CISA KEV
AI summary
Written by an external AI model and may contain mistakes. Check the original description and references below before acting on it.
A critical vulnerability has been identified in the Linux kernel that allows unauthorized access by non-privileged users. This could result in system compromise if not patched promptly. Similar issues have been exploited before, emphasizing the importance of immediate action, especially in cloud services and corporate environments.
A vulnerability in the Linux kernel's algif_aead module allows unauthorized access through the AF_ALG API, enabling users to perform a 4-byte page cache write to any file. Affected versions range from 4.14, with fixes in 6.18.22 and 6.19.12. As a workaround, adding "install algif_aead /bin/false" to /etc/modprobe.d/disable-algif-aead.conf can disable the kernel module.
Vulnerability in the Linux kernel's algif_aead encryption module allowing unauthorized page cache writes.
AF_ALG API, algif_aead module of the Linux kernel.
High severity vulnerability with potential for privilege escalation to root.
Patch kernels to version 6.19.12 or apply backported fixes. Disable algif_aead module as a workaround.
Disable algif_aead kernel module by setting "install algif_aead /bin/false" in /etc/modprobe.d/disable-algif-aead.conf.
Detection can be done by inspecting kernel versioning and system logs for unauthorized kernel module usage.
Related past incidents Similar incidents extracted from past CVEs
A similar privilege escalation vulnerability in Linux, allowing bypass of file checks to gain root access.
A famous Linux privilege escalation bug leveraging a race condition for root access.
A vulnerability in Linux kernel affecting cryptographic subsystem, similar in usage of page cache.
If this happens at your company Expected impact per business scenario
Unauthorized users may escalate privileges, affecting data integrity and system security.
Compromised user accounts could lead to broader network access and data breaches.
Malicious actors could alter build processes, impacting software integrity.
Immediately apply available patches and ensure kernel modules like algif_aead are disabled if not actively used.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'redhat' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
redhatを grep し、稼働しているサービス・バージョンを把握する。 -
4Consider incident declaration escalate
Notify SOC / on-callCISA KEV登録済 = 実環境で悪用が観測されている。Step 3 で兆候があればインシデント対応宣言、無くてもパッチ適用までWAF強化を最優先で。
-
7Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 3 と同じログクエリでアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- BellSoft Alpaquita BELL-CVE-2026-31431 linux-lts Fixed in: 6.1.170-r0
- Debian DEBIAN-CVE-2026-31431 linux Fixed in: 5.10.251-3
- Ubuntu UBUNTU-CVE-2026-31431 linux-azure Fixed in: 4.15.0-1201.216~14.04.1
References
- AWS aws.amazon.com
- AWS aws.amazon.com
- ICSA cisa.gov
- patch lore.kernel.org
- web nvd.nist.gov
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web openwall.com
- web openwall.com
- web openwall.com
- web openwall.com
- web openwall.com
- web openwall.com
- web openwall.com
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- web openwall.com
- web openwall.com
- web openwall.com
- web openwall.com
- web openwall.com
- web openwall.com
- web openwall.com
- web openwall.com
- web copy.fail
- web websec.net
- web kb.cert.org
- web access.redhat.com
- web github.com
- web cisa.gov
- web xint.io
- web lore.kernel.org
- web github.com
- web cert-portal.siemens.com
- web cert-portal.siemens.com
- web openwall.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web bugzilla.redhat.com
- web security.access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
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- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web access.redhat.com
- web cert-portal.siemens.com
- web cert-portal.siemens.com