CVE-2026-31681

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.

• linux linux kernel (>= 2.6.17 < 6.6.136) • linux linux kernel (>= 6.7 < 6.12.83) • linux linux kernel (>= 6.13 < 6.18.24) • linux linux kernel (>= 6.19 < 6.19.14) • linux linux kernel 7.0