CVE-2025-39768: In the Linux kernel, the following vulnerability has been resolved: net/mlx5: HWS, fix complex rules rehash error flow Moving rules from matcher to ...

Description

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: HWS, fix complex rules rehash error flow Moving rules from matcher to matcher should not fail. However, if it does fail due to various reasons, the error flow should allow the kernel to continue functioning (albeit with broken steering rules) instead of going into series of soft lock-ups or some other problematic behaviour. Similar to the simple rules, complex rules rehash logic suffers from the same problems. This patch fixes the error flow for moving complex rules: - If new rule creation fails before it was even enqeued, do not poll for completion - If TIMEOUT happened while moving the rule, no point trying to poll for completions for other rules. Something is broken, completion won't come, just abort the rehash sequence. - If some other completion with error received, don't give up. Continue handling rest of the rules to minimize the damage. - Make sure that the first error code that was received will be actually returned to the caller instead of replacing it with the generic error code. All the aforementioned issues stem from the same bad error flow, so no point fixing them one by one and leaving partially broken code - fixing them in one patch.

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

0.12%

2.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-617

Affected Software

Vendor	Product	Versions	Update
Linux	Linux Kernel	>= 6.16, < 6.16.4	—
Linux	Linux Kernel	6.17	Rc1

References

Timeline

Published: Sep 11, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-39768?

In the Linux kernel, the following vulnerability has been resolved: net/mlx5: HWS, fix complex rules rehash error flow Moving rules from matcher to matcher should not fail. However, if it does fail due to various reasons, the error flow should allow the kernel to continue functioning (albeit with broken steering rules) instead of going into series of soft lock-ups or some other problematic behaviour. Similar to the simple rules, complex rules rehash logic suffers from the same problems. This patch fixes the error flow for moving complex rules: - If new rule creation fails before it was even enqeued, do not poll for completion - If TIMEOUT happened while moving the rule, no point trying to poll for completions for other rules. Something is broken, completion won't come, just abort the rehash sequence. - If some other completion with error received, don't give up. Continue handling rest of the rules to minimize the damage. - Make sure that the first error code that was received will be actually returned to the caller instead of replacing it with the generic error code. All the aforementioned issues stem from the same bad error flow, so no point fixing them one by one and leaving partially broken code - fixing them in one patch.

How severe is CVE-2025-39768?

CVE-2025-39768 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.12% probability of exploitation in the next 30 days.

How do I fix CVE-2025-39768?

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.