CVE-2026-99244: Linux kernel · pid_namespace: prevent TIF_NOTIFY_SIGNAL from interrupting the reaper
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 5 Nov 2026, 00:01 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Thin evidence
One scorer or none- EPSS
- 0.1% chance of exploitation in 30 days – higher than 9% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 3 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix has been implemented in the Linux kernel to address this issue by introducing a no_notify_signal guard that prevents TIF_NOTIFY_SIGNAL from interrupting the reaper. Users should apply the updated kernel versions containing this fix to mitigate the vulnerability.
Description
CVE-2026-99244 is a vulnerability in the Linux kernel's pid_namespace handling where the TIF_NOTIFY_SIGNAL flag can interrupt the reaper process improperly. The issue arises because the TIF_NOTIFY_SIGNAL flag can be set repeatedly during livepatching, causing the reaper to busy-wait and preventing it from sleeping as intended. This leads to a situation where the reaper's sleep loop is interrupted, potentially affecting process reaping behavior.
References
- ubuntu.com/security/CVE-2026-99244 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99244 (opens in a new tab)
- git.kernel.org/stable/c/30b274508c743f243c82904954c4e416d7143d4c (opens in a new tab)
- git.kernel.org/stable/c/3d15ac36ce174477efa5365e424dbd47950fd2b9 (opens in a new tab)
- git.kernel.org/stable/c/70178691c467c8f9f722765299fd8524c3121a35 (opens in a new tab)
- git.kernel.org/stable/c/9ab0324f4868eeb20c63f063a1e5bc01d5539212 (opens in a new tab)
- git.kernel.org/stable/c/f46cd8241d9b83f2279cc0db3e9d3e181b548a59 (opens in a new tab)
- git.kernel.org/stable/c/2c20ace1698d03a23467351be1d281e89b36ade3 (opens in a new tab)