CVE-2026-45915: Linux kernel · fat: avoid parent link count underflow in rmdir
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in d3b7ffa90f613938128432c7b2f35b7aa4bdd86b : update Linux kernel when convenient.
Data as of 6 Nov 2026, 16:05 UTC
Rated Low by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-06.
- Patch
- Available – fixed in d3b7ffa90f613938128432c7b2f35b7aa4bdd86b, d0bb592fa9def2bace90ac8926c0a1d6fa8c1aa0, cd569b87378b9c33ae13c23d6bb9d205d66f7c4b +5
Exploitation evidence
Disclosed: evidence found.
CVE published 27 May 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 6 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
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
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
A fix is available and has been applied in the Linux kernel. Users should update to a kernel version that includes the fix identified by the listed commit hashes. No additional mitigation is required once the kernel is updated.
Description
A vulnerability in the Linux kernel's FAT filesystem handling could cause an underflow of the parent directory's link count during the rmdir operation. This occurs when corrupted FAT images leave a directory inode with an incorrect link count, leading rmdir to improperly decrement the count and trigger a kernel warning. The issue is fixed by adding a sanity check to only decrement the parent link count when it is at least 3, otherwise reporting a filesystem error.
References
- git.kernel.org/stable/c/7fe0de287e931e07cb96ecf1f449b2ebdb0e1115 (opens in a new tab)
- git.kernel.org/stable/c/9894c79fd9466612d0514be157b5c30cd93aa645 (opens in a new tab)
- git.kernel.org/stable/c/cd569b87378b9c33ae13c23d6bb9d205d66f7c4b (opens in a new tab)
- git.kernel.org/stable/c/d3b7ffa90f613938128432c7b2f35b7aa4bdd86b (opens in a new tab)
- git.kernel.org/stable/c/955c5d670b5ae07c78f4345e23a895638db96ce1 (opens in a new tab)
- git.kernel.org/stable/c/17866f8a0822d414cb02e621cf003a7d04396ef8 (opens in a new tab)
- git.kernel.org/stable/c/d0bb592fa9def2bace90ac8926c0a1d6fa8c1aa0 (opens in a new tab)
- git.kernel.org/stable/c/8cafcb881364af5ef3a8b9fed4db254054033d8a (opens in a new tab)