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Fencer Vulns
no cvss —

CVE-2026-99244 json

pid_namespace: prevent TIF_NOTIFY_SIGNAL from interrupting the reaper

published 2026-11-03 5 d ago modified 2026-11-03 5 d ago also EUVD-2026-115774

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

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.

Patch / fix

  • Linux Linux 5.11, 5.16, 6.1.191, 6.6.161, 6.10, 6.12.115, 6.18.60, 7.2.14, 7.3.1, 7.4-rc1
  • linux Debian 13 6.12.115-1
  • linux Debian 14 7.2.14-1

debian advisories DEBIAN-CVE-2026-99244

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-99244 updated cvss 3.3

kernel: kernel: Denial of Service via busy-wait loop during PID namespace cleanup

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-10
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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