What’s Vulnerable › Vulnerabilities

CVE-2026-45915: fat: avoid parent link count underflow in rmdir

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-27 · updated 2026-06-24

Description

In the Linux kernel, the following vulnerability has been resolved: fat: avoid parent link count underflow in rmdir Corrupted FAT images can leave a directory inode with an incorrect i_nlink (e.g. 2 even though subdirectories exist). rmdir then unconditionally calls drop_nlink(dir) and can drive i_nlink to 0, triggering the WARN_ON in drop_nlink(). Add a sanity check in vfat_rmdir() and msdos_rmdir(): only drop the parent link count when it is at least 3, otherwise report a filesystem error.

Affected products

• Linux kernel: from 2.6.19 before 5.10.252; from 5.11 before 5.15.202; from 5.16 before 6.1.165; from 6.2 before 6.6.128; from 6.7 before 6.12.75; from 6.13 before 6.18.14 — fixed in 5.10.252, 5.15.202, 6.1.165, 6.12.75, 6.18.14, 6.19.4

How to fix

Upgrade to a fixed version: Linux kernel 5.10.252, 5.15.202, 6.1.165, 6.12.75. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/17866f8a0822d414cb02e621cf003a7d04396ef8
• https://git.kernel.org/stable/c/7fe0de287e931e07cb96ecf1f449b2ebdb0e1115
• https://git.kernel.org/stable/c/8cafcb881364af5ef3a8b9fed4db254054033d8a
• https://git.kernel.org/stable/c/955c5d670b5ae07c78f4345e23a895638db96ce1
• https://git.kernel.org/stable/c/9894c79fd9466612d0514be157b5c30cd93aa645
• https://git.kernel.org/stable/c/cd569b87378b9c33ae13c23d6bb9d205d66f7c4b
• https://git.kernel.org/stable/c/d0bb592fa9def2bace90ac8926c0a1d6fa8c1aa0
• https://git.kernel.org/stable/c/d3b7ffa90f613938128432c7b2f35b7aa4bdd86b

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