# CVE-2026-99244: pid_namespace: prevent TIF_NOTIFY_SIGNAL from interrupting the reaper

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

In the Linux kernel, the following vulnerability has been resolved:

pid_namespace: prevent TIF_NOTIFY_SIGNAL from interrupting the reaper

Since commit 7fea700e04bd ("zap_pid_ns_processes: clear
TIF_NOTIFY_SIGNAL along with TIF_SIGPENDING") zap_pid_ns_processes()
clears TIF_NOTIFY_SIGNAL before every kernel_wait4() call. Otherwise
kernel_wait4() doesn't sleep and returns -ERESTARTSYS if
signal_pending() is true and the reaper busy-waits.

But clearing TIF_NOTIFY_SIGNAL doesn't fix it. It can get raised again.
For example, klp_send_signals() sets it raw against any task that hasn't
transitioned yet. And it keeps sending it until the livepatch finishes.

The sleep loop waiting for pid_allocated to drop has the same problem
and it doesn't even clear anything. So a schedule() in
TASK_INTERRUPTIBLE returns immediately.

Use a no_notify_signal guard. signal_pending() will ignore
TIF_NOTIFY_SIGNAL and the pid namespace reaper sleeps until a child
exits or free_pid() wakes it.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ edd2754a62bee8d97b4808a15de024f66a1ddccf; < 2c20ace1698d03a23467351be1d281e89b36ade3 (affected, git); ≥ 3466abafa9f4f81a869da828e52a12f693175ec2; < 9ab0324f4868eeb20c63f063a1e5bc01d5539212 (affected, git); ≥ 7fea700e04bd3f424c2d836e98425782f97b494e; < 30b274508c743f243c82904954c4e416d7143d4c (affected, git); ≥ 7fea700e04bd3f424c2d836e98425782f97b494e; < 70178691c467c8f9f722765299fd8524c3121a35 (affected, git); ≥ 7fea700e04bd3f424c2d836e98425782f97b494e; < 3d15ac36ce174477efa5365e424dbd47950fd2b9 (affected, git); ≥ 7fea700e04bd3f424c2d836e98425782f97b494e; < f46cd8241d9b83f2279cc0db3e9d3e181b548a59 (affected, git); 82c7acf9a12c9b4e4b0aba531de82b4e39a345c8 (affected, git); 8e69e589f233ca2c9631f5af2b94f95dfc2ba804 (affected, git); 09ab5b424b17cfe633db58bb2f9edbaf9484cf20 (affected, git); ≥ 6.1.95; < 6.1.191 (affected, semver); ≥ 6.6.35; < 6.6.161 (affected, semver); ≥ 5.10.221; < 5.11 (affected, semver); ≥ 5.15.162; < 5.16 (affected, semver); ≥ 6.9.6; < 6.10 (affected, semver). Source: CNA: Linux
- Linux / Linux: 6.10 (affected); ≥ 0; < 6.10 (unaffected, semver); ≥ 6.1.191; ≤ 6.1.* (unaffected, semver); ≥ 6.6.161; ≤ 6.6.* (unaffected, semver); ≥ 6.12.115; ≤ 6.12.* (unaffected, semver); ≥ 6.18.60; ≤ 6.18.* (unaffected, semver); ≥ 7.2.14; ≤ 7.2.* (unaffected, semver); ≥ 7.3.1; ≤ 7.3.* (unaffected, semver). 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/2c20ace1698d03a23467351be1d281e89b36ade3 (CNA: Linux)

- https://git.kernel.org/stable/c/9ab0324f4868eeb20c63f063a1e5bc01d5539212 (CNA: Linux)

- https://git.kernel.org/stable/c/30b274508c743f243c82904954c4e416d7143d4c (CNA: Linux)

- https://git.kernel.org/stable/c/70178691c467c8f9f722765299fd8524c3121a35 (CNA: Linux)

- https://git.kernel.org/stable/c/3d15ac36ce174477efa5365e424dbd47950fd2b9 (CNA: Linux)

- https://git.kernel.org/stable/c/f46cd8241d9b83f2279cc0db3e9d3e181b548a59 (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-99244; retrieved 2026-11-03; source updated 2026-11-03

Revision: 5467867fbfcca07e16ca582d11a8da48de5c3dfee887ab980f715c1dda236838

Canonical: https://y2.dev/cve/CVE-2026-99244

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