CVE-2026-31681
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_multiport: validate range encoding in checkentry ports_match_v1() treats any non-zero pflags entry as the start of a port range and unconditionally consumes the next ports[] element as the range end. The checkentry path currently validates protocol, flags and count, but it does not validate the range encoding itself. As a result, malformed rules can mark the last slot as a range start or place two range starts back to back, leaving ports_match_v1() to step past the last valid ports[] element while interpreting the rule. Reject malformed multiport v1 rules in checkentry by validating that each range start has a following element and that the following element is not itself marked as another range start.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | affected | |
| debian | bullseye | affected | |
| debian | forky | fixed | 6.19.14-1 |
| debian | sid | fixed | 6.19.14-1 |
| debian | trixie | fixed | 6.12.85-1 |
| linux-kernel | affected | 6.6.136 | |
| linux-kernel | 7.0 | affected | |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| gcp | | |
References
- https://git.kernel.org/stable/c/1e4baa853f1cc4227e04f52d6860524707cfb294
- https://git.kernel.org/stable/c/36bf0d98e180a7c384c8d8a59b0d2d4b80e5eb16
- https://git.kernel.org/stable/c/8368ce8eb01f0b91111d814703696e780d0ef12f
- https://git.kernel.org/stable/c/aec14808271f2bf2b656de6ff12dfe73c5fd3b67
- https://git.kernel.org/stable/c/ff64c5bfef12461df8450e0f50bb693b5269c720
- https://www.suse.com/security/cve/CVE-2026-31681.html
- https://security-tracker.debian.org/tracker/CVE-2026-31681
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.