CVE-2025-39768

CVE-2025-39768 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. The underlying weakness is classified as CWE-617.

Key facts

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.

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 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-2025-39768 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-39768?
CVE-2025-39768 primarily affects Linux Linux Kernel. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-39768?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-39768 have an EU (EUVD) identifier?
Yes. CVE-2025-39768 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-28944.
When was CVE-2025-39768 published?
CVE-2025-39768 was published on 2025-09-11 and last updated on 2026-06-17.

References

Affected products (3)

More vulnerabilities in Linux Linux Kernel

All CVEs affecting Linux Linux Kernel →

Other CWE-617 (Reachable Assertion) vulnerabilities

Browse all CWE-617 (Reachable Assertion) vulnerabilities →