# CVE-2026-99249: pid_namespace: make zap_pid_ns_processes() freezable

CVE-2026-99249 is fixed in linux on 1 platform by DEBIAN-CVE-2026-99249 (version 6.12.115-1), released November 3, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-99249
- Priority: Routine
- CVSS: 2.5 (Low)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Nov 3, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99249

## Description

In the Linux kernel, the following vulnerability has been resolved:  pid_namespace: make zap_pid_ns_processes() freezable  When the init of a pid namespace exits, zap_pid_ns_processes() waits until all other pids in the namespace are freed. A tracer outside the namespace that does not reap its traced zombies keeps those pids allocated, so this wait has no upper bound, and while it lasts every suspend attempt fails:    Freezing user space processes failed after 20.006 seconds (2 tasks refusing to freeze, wq_busy=0):  Neither wait is freezable. The first loop sleeps in do_wait(), which returns -ERESTARTSYS on the freezer's fake signal; the loop then clears TIF_SIGPENDING and waits again without ever freezing. The final loop sleeps in TASK_INTERRUPTIBLE, and since nothing clears TIF_SIGPENDING there, schedule() returns immediately after the first freeze attempt and the task spins until the wait ends.  Sleep in TASK_INTERRUPTIBLE | TASK_FREEZABLE in do_wait(), so that the freezer can freeze tasks waiting there directly, and in TASK_IDLE | TASK_FREEZABLE in the final loop, like coredump_task_exit() does.  This was hit with Chromium-based browsers: crashpad ptrace-attaches the threads of a crashed renderer, which is a pid namespace init, and does not reap those killed during the dump.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.115-1 | [DEBIAN-CVE-2026-99249](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99249.md) | Nov 3, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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