CVE-2025-40139

  • Published: 2025-11-12T11:15:43.677

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.

Related CVE by CWE

No related CWE found.

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How to fix CVE-2025-40139

CVE-2025-40139 is a unknown severity vulnerability affecting the affected product.

Description: 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 […]

Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public

How to Fix:

1 Identify affected systems

- Check if you're running the affected product

2 Immediate actions

- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access

3 Verification

- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)

4 Long-term prevention

- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations

Exploit Difficulty Assessment

HARD
⏱️ Time to Exploit: > 4 hours
🛠️ Skills Required: Advanced security expertise
💰 Public Exploits: Rare or not public

Vulnerability Timeline

Nov 12, 2025
Vulnerability Published

CVE details first published to NVD database

Nov 12, 2025
Imported to Database

Added to this CVE tracking system

Detection Rules & IOCs

No specific detection rules generated for this vulnerability type.

No vendor/product data available.