CVE-2023-53484: lib: cpu_rmap: Avoid use after free on rmap->obj array entries

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: 2025-10-01 · updated 2026-10-15
Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: lib: cpu_rmap: Avoid use after free on rmap->obj array entries When calling irq_set_affinity_notifier() with NULL at the notify argument, it will cause freeing of the glue pointer in the corresponding array entry but will leave the pointer in the array. A subsequent call to free_irq_cpu_rmap() will try to free this entry again leading to possible use after free. Fix that by setting NULL to the array entry and checking that we have non-zero at the array entry when iterating over the array in free_irq_cpu_rmap(). The current code does not suffer from this since there are no cases where irq_set_affinity_notifier(irq, NULL) (note the NULL passed for the notify arg) is called, followed by a call to free_irq_cpu_rmap() so we don't hit and issue. Subsequent patches in this series excersize this flow, hence the required fix.

Affected products

Linux kernel: from 3.8.1 before 4.14.316; from 4.15 before 4.19.284; from 4.20 before 5.4.244; from 5.5 before 5.10.181; from 5.11 before 5.15.113; from 5.16 before 6.1.30 — fixed in 4.14.316, 4.19.284, 5.10.181, 5.15.113, 5.4.244, 6.1.30

How to fix

Upgrade to a fixed version: Linux kernel 4.14.316, 4.19.284, 5.10.181, 5.15.113. Check the vendor advisory for mitigations.

References

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