CVE-2025-39768: Linux kernel · net/mlx5: HWS, fix complex rules rehash error flow
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 26 Oct 2026, 13:47 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-gcp-6.11pkg:deb/ubuntu/linux-gcp-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-hwe-6.11pkg:deb/ubuntu/linux-hwe-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-intelpkg:deb/ubuntu/linux-intel?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinux-lowlatency-hwe-6.11pkg:deb/ubuntu/linux-lowlatency-hwe-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- ubuntu.com/security/CVE-2025-39768 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-39768 (opens in a new tab)
- git.kernel.org/linus/4a842b1bf18a32ee0c25dd6dd98728b786a76fe4 (opens in a new tab)
- git.kernel.org/stable/c/37d54bc28d092bc3b314da45d730f00e9d86ec2a (opens in a new tab)
- git.kernel.org/stable/c/4a842b1bf18a32ee0c25dd6dd98728b786a76fe4 (opens in a new tab)