CVE-2026-98979: Linux kernel · namespace: refuse an automount below a mount that is in no namespace
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 28 Oct 2026, 02:00 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
Exploitation evidence
Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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 is available that replaces the faulty mount namespace check with is_mounted(), which rejects unmounted and internal mounts. This causes the open operation to fail with EINVAL instead of crashing the kernel. Users should apply the updated Linux kernel versions that include this fix. No additional mitigation is required as the vulnerability is resolved in these patched versions.
Description
CVE-2026-98979 is a vulnerability in the Linux kernel's namespace handling where an automount can be added below a mount that is not in the caller's mount namespace. This flaw allows dereferencing an error pointer leading to a kernel crash (general protection fault) and a null pointer dereference. The issue occurs during mount operations and can block all mount operations system-wide while the namespace semaphore is held. The problem is triggered via fanotify and overlay filesystem interactions. The fix involves using is_mounted() to reject unmounted and internal mounts, causing the open to fail gracefully with EINVAL as before.
References
- ubuntu.com/security/CVE-2026-98979 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-98979 (opens in a new tab)
- git.kernel.org/stable/c/35f2013f83ef16f9f0331c4c3a8e8d161580d574 (opens in a new tab)
- git.kernel.org/stable/c/494c57572d2d5bc2839553ed41aabe92ed0f587c (opens in a new tab)
- git.kernel.org/stable/c/776e20e4fdc23c23687b511ffdc80047878049d3 (opens in a new tab)
- git.kernel.org/stable/c/95fb7c259b86f5521f04973040ad492f2bef6f82 (opens in a new tab)
- git.kernel.org/stable/c/ba985ce08471c555af2a2fbe217c1bc2e72a6d8c (opens in a new tab)