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CVE-2026-45861: gfs2: Fix slab-use-after-free in qd_put

• Severity: high (CVSS 7.8 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 2026-10-21
• Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix slab-use-after-free in qd_put Commit a475c5dd16e5 ("gfs2: Free quota data objects synchronously") started freeing quota data objects during filesystem shutdown instead of putting them back onto the LRU list, but it failed to remove these objects from the LRU list, causing LRU list corruption. This caused use-after-free when the shrinker (gfs2_qd_shrink_scan) tried to access already-freed objects on the LRU list. Fix this by removing qd objects from the LRU list before freeing them in qd_put(). Initial fix from Deepanshu Kartikey <kartikey406@gmail.com>.

Affected products

• Linux kernel: from 6.6 before 6.12.75; from 6.13 before 6.18.14; from 6.19 before 6.19.4 — fixed in 6.12.75, 6.18.14, 6.19.4

How to fix

Upgrade to a fixed version: Linux kernel 6.12.75, 6.18.14, 6.19.4. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/1d47922b98046b8070a77347fb883a6523792803
• https://git.kernel.org/stable/c/22150a7d401d9e9169b9b68e05bed95f7f49bf69
• https://git.kernel.org/stable/c/53aaf083de197946b25bc4ffa3068d37366ce73d
• https://git.kernel.org/stable/c/80fff26d7a0c3926b511661c27eecc811a420eef
• https://git.kernel.org/stable/c/ca7c67bdd293089b3483f18886d6b2d0037d2ad9

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