Vulnerability 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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 2.6.17, < 6.6.136 |
References
- https://git.kernel.org/stable/c/1e4baa853f1cc4227e04f52d6860524707cfb294Patch
- https://git.kernel.org/stable/c/36bf0d98e180a7c384c8d8a59b0d2d4b80e5eb16Patch
- https://git.kernel.org/stable/c/8368ce8eb01f0b91111d814703696e780d0ef12fPatch
- https://git.kernel.org/stable/c/aec14808271f2bf2b656de6ff12dfe73c5fd3b67Patch
- https://git.kernel.org/stable/c/ff64c5bfef12461df8450e0f50bb693b5269c720Patch
FAQ
What is CVE-2026-31681?
CVE-2026-31681 is a vulnerability with a CVSS score of 5.5 (MEDIUM). 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...
How severe is CVE-2026-31681?
CVE-2026-31681 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-31681?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.