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CVE-2025-39926

MEDIUMCVSS 5.5/10EPSS 0.13%

Last modified

CVE-2025-39926 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. 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. EPSS estimates a 0.13% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
0.13%

3.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersionsUpdate
LinuxLinux Kernel>= 6.9, < 6.12.48—
LinuxLinux Kernel>= 6.13, < 6.16.8—
LinuxLinux Kernel6.17Rc1

References

Timeline

Published
Last Modified
Status
Modified

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 score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.13% probability of exploitation in the next 30 days.
How do I fix CVE-2025-39926?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-39926?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST