CVE-2025-39926

CVE-2025-39926 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: genetlink: fix genl_bind() invoking bind() after -EPERM Per family bind/unbind callbacks were introduced to allow families to track multicast group consumer presence, e.g. to start or stop producing events depending on listeners. However, in genl_bind() the bind() callback was invoked even if capability checks failed and ret was set to -EPERM. This means that callbacks could run on behalf of unauthorized callers while the syscall still returned failure to user space. Fix this by only invoking bind() after "if (ret) break;" check i.e. after permission checks have succeeded.

Frequently asked questions

What is CVE-2025-39926?
In the Linux kernel, the following vulnerability has been resolved: genetlink: fix genl_bind() invoking bind() after -EPERM Per family bind/unbind callbacks were introduced to allow families to track multicast group consumer presence, e.g. to start or stop producing events depending on listeners. However, in genl_bind() the bind() callback was invoked even if capability checks failed and ret was set to -EPERM. This means that callbacks could run on behalf of unauthorized callers while the syscall still returned failure to user space. Fix this by only invoking bind() after "if (ret) break;" check i.e. after permission checks have succeeded.
How severe is CVE-2025-39926?
CVE-2025-39926 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-39926 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-39926?
CVE-2025-39926 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-39926?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-39926 have an EU (EUVD) identifier?
Yes. CVE-2025-39926 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-32879.
When was CVE-2025-39926 published?
CVE-2025-39926 was published on 2025-10-01 and last updated on 2026-06-17.

References

Affected products (6)

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