CVE-2026-99175: Linux kernel · fsnotify: prevent mark additions during connector teardown
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 30 Oct 2026, 03:46 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Thin evidence
One scorer or noneExploitation evidence
Disclosed: evidence found.
CVE published 28 Oct 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 29 Oct 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 for this vulnerability has been implemented in the Linux kernel by adding a DESTROYING flag to prevent new marks during connector teardown and adjusting locking mechanisms. Users should apply the updated kernel versions that include this fix. No additional mitigation is required beyond updating to the fixed versions.
Description
CVE-2026-99175 is a vulnerability in the Linux kernel's fsnotify subsystem where marks could be added during connector teardown, leading to a race condition. This flaw could cause a null pointer dereference (KASAN BUG) during an unprivileged file descriptor info read operation, potentially destabilizing the kernel. The issue arises because the walk cursor used during mark destruction does not prevent new marks from being inserted, which can cause the connector to detach improperly. The vulnerability has been resolved by introducing a DESTROYING flag to prevent new marks during teardown and adjusting locking to avoid races.
References
- ubuntu.com/security/CVE-2026-99175 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-99175 (opens in a new tab)
- git.kernel.org/stable/c/952501bfc6e5e654ac4a17ec9d90c1ec614bd9f1 (opens in a new tab)
- git.kernel.org/stable/c/36ebddca56b9d8993d6dc984fdecc748ee1f5e06 (opens in a new tab)
- git.kernel.org/stable/c/472589eacdf10b5f9bd10b333957ed5291b2544b (opens in a new tab)