CVE-2026-53341: Linux kernel · fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh()
Source GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in a8ed2c29fcfdac78db96c9da4e659c8a513f2a94 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in a8ed2c29fcfdac78db96c9da4e659c8a513f2a94, 32138633e51e6db59e474765cf93268c92b42888, 40ab6644b99685755f740b872c00ef40d9aa870e +1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 1 Jul 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
Upgrade Linux kernel to a8ed2c29fcfdac78db96c9da4e659c8a513f2a94, 32138633e51e6db59e474765cf93268c92b42888, 40ab6644b99685755f740b872c00ef40d9aa870e or 15ea8dc42a02259d49dee38a658d40f60fcd75ed.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix is available that adds proper RCU locking around the mount::mnt_ns access in may_decode_fh() and uses WRITE_ONCE() for writers to prevent races. Users should apply the official kernel updates that include this fix. Since this is a kernel vulnerability, updating to a patched kernel version is the recommended mitigation. Patch status is not explicitly confirmed in the provided data; check the vendor advisory for current remediation guidance.
Description
A use-after-free (UAF) vulnerability in the Linux kernel's may_decode_fh() function was resolved. The issue arises because may_decode_fh() accesses mount::mnt_ns without proper locking, allowing a race condition where the mount namespace can be freed concurrently. This race requires specific kernel configurations (CONFIG_PREEMPTION or CONFIG_RCU_STRICT_GRACE_PERIOD) and an RCU grace period during a syscall. The vulnerability could lead to leaking an integer comparison result, cause an endless loop, or crash the kernel by dereferencing invalid memory.
References
- nvd.nist.gov/vuln/detail/CVE-2026-53341 (opens in a new tab)
- git.kernel.org/stable/c/15ea8dc42a02259d49dee38a658d40f60fcd75ed (opens in a new tab)
- git.kernel.org/stable/c/32138633e51e6db59e474765cf93268c92b42888 (opens in a new tab)
- git.kernel.org/stable/c/40ab6644b99685755f740b872c00ef40d9aa870e (opens in a new tab)
- git.kernel.org/stable/c/a8ed2c29fcfdac78db96c9da4e659c8a513f2a94 (opens in a new tab)