CVE-2022-49425: f2fs: fix dereference of stale list iterator after loop body

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-26 · updated 2026-08-04
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix dereference of stale list iterator after loop body The list iterator variable will be a bogus pointer if no break was hit. Dereferencing it (cur->page in this case) could load an out-of-bounds/undefined value making it unsafe to use that in the comparision to determine if the specific element was found. Since 'cur->page' *can* be out-ouf-bounds it cannot be guaranteed that by chance (or intention of an attacker) it matches the value of 'page' even though the correct element was not found. This is fixed by using a separate list iterator variable for the loop and only setting the original variable if a suitable element was found. Then determing if the element was found is simply checking if the variable is set.

Affected products

Linux kernel: from 4.12 before 4.19.247; from 4.20 before 5.4.198; from 5.5 before 5.10.121; from 5.11 before 5.15.46; from 5.16 before 5.17.14; from 5.18 before 5.18.3 — fixed in 4.19.247, 5.10.121, 5.15.46, 5.17.14, 5.18.3, 5.4.198

How to fix

Upgrade to a fixed version: Linux kernel 4.19.247, 5.10.121, 5.15.46, 5.17.14. Check the vendor advisory for mitigations.

References

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