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

Status: published. Published: 2026-11-03. Updated: 2026-11-03.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 3eb07c8c8adb6f0572baba844ba2d9e501654316; < 064a6761d6f6ac55d090d3eaca649577ee736713 (affected, git); ≥ 3eb07c8c8adb6f0572baba844ba2d9e501654316; < e8dafad7de9ede813af2d48cc04b7c88fef16682 (affected, git); ≥ 3eb07c8c8adb6f0572baba844ba2d9e501654316; < 4b47107f1a80c809c80093e872bcaccdbae13db4 (affected, git); ≥ 3eb07c8c8adb6f0572baba844ba2d9e501654316; < 2e10b8a74f55b5aae33db105d3e2d3ae759c865a (affected, git); ≥ 3eb07c8c8adb6f0572baba844ba2d9e501654316; < 7deb5770840339fe88755bf27b92f74edc26ee87 (affected, git); ≥ 3eb07c8c8adb6f0572baba844ba2d9e501654316; < 81933038f5e273d17ed22792f906889393b204c5 (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.24 (affected); ≥ 0; < 2.6.24 (unaffected, semver); ≥ 6.1.191; ≤ 6.1.* (unaffected, semver); ≥ 6.6.161; ≤ 6.6.* (unaffected, semver); ≥ 6.12.115; ≤ 6.12.* (unaffected, semver); ≥ 6.18.59; ≤ 6.18.* (unaffected, semver); ≥ 7.2.13; ≤ 7.2.* (unaffected, semver); ≥ 7.3; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/064a6761d6f6ac55d090d3eaca649577ee736713 (CNA: Linux)

- https://git.kernel.org/stable/c/e8dafad7de9ede813af2d48cc04b7c88fef16682 (CNA: Linux)

- https://git.kernel.org/stable/c/4b47107f1a80c809c80093e872bcaccdbae13db4 (CNA: Linux)

- https://git.kernel.org/stable/c/2e10b8a74f55b5aae33db105d3e2d3ae759c865a (CNA: Linux)

- https://git.kernel.org/stable/c/7deb5770840339fe88755bf27b92f74edc26ee87 (CNA: Linux)

- https://git.kernel.org/stable/c/81933038f5e273d17ed22792f906889393b204c5 (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-99249; retrieved 2026-11-03; source updated 2026-11-03

Revision: 4ef4dd570f01d2e81af79825edf14ee6bf4b7a759e6be2c03684a56e92d7a215

Canonical: https://y2.dev/cve/CVE-2026-99249

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