smc: Use __sk_dst_get() and dst_dev_rcu() in in smc_clc_prfx_set().
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 3 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: smc: Use __sk_dst_get() and dst_dev_rcu() in in smc_clc_prfx_set(). smc_clc_prfx_set() is called during connect() and not under RCU nor RTNL. Using sk_dst_get(sk)->dev could trigger UAF. Let's use __sk_dst_get() and dev_dst_rcu() under rcu_read_lock() after kernel_getsockname(). Note that the returned value of smc_clc_prfx_set() is not used in the caller. While at it, we change the 1st arg of smc_clc_prfx_set[46]_rcu() not to touch dst there.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.187, 6.6.156, 6.12.108, 6.17.3, 6.18
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2025-40139
- 2026-10-03 Alias added: GHSA-ffj5-vpjf-2hxm
- 2026-10-16 CISA SSVC decision points changed
References
Other 5
- https://git.kernel.org/stable/c/5a2fccc4b32c13ddde3676f9e15e1a9baa7d6fde
- https://git.kernel.org/stable/c/80d1fd39f4e37d836655e9f7ffccaf78925049bf
- https://git.kernel.org/stable/c/956c57daba55cf9ed25d9f2512883b8a1a927599
- https://git.kernel.org/stable/c/0736993bfe5c7a9c744ae3fac62d769dfdae54e1
- https://git.kernel.org/stable/c/935d783e5de9b64587f3adb25641dd8385e64ddb
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Sources
- CVE-2025-40139 · CVE Program
- CVE-2025-40139 · NVD
- FIRST EPSS
- GHSA-ffj5-vpjf-2hxm · GitHub Advisory Database · CC BY 4.0
- CVE-2025-40139 · Red Hat security data · CC BY 4.0
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