Linux vulnerability

What happened

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.

Affected versions

Linux: a89ecb6a2ef732d04058d87801e2b6bd7e5c7089 through before 8c5bf8f5b478f569191c4a7982de7cd5f5f73c1a (git); a89ecb6a2ef732d04058d87801e2b6bd7e5c7089 through before c9749f6232c845e31c21d4cc72200211df15d8a2 (git); a89ecb6a2ef732d04058d87801e2b6bd7e5c7089 through before b67d638cbee9975c765feb45c126e96ed11ec802 (git); a89ecb6a2ef732d04058d87801e2b6bd7e5c7089 through before 36bf0d98e180a7c384c8d8a59b0d2d4b80e5eb16 (git); a89ecb6a2ef732d04058d87801e2b6bd7e5c7089 through before aec14808271f2bf2b656de6ff12dfe73c5fd3b67 (git); a89ecb6a2ef732d04058d87801e2b6bd7e5c7089 through before 8368ce8eb01f0b91111d814703696e780d0ef12f (git); a89ecb6a2ef732d04058d87801e2b6bd7e5c7089 through before 1e4baa853f1cc4227e04f52d6860524707cfb294 (git); a89ecb6a2ef732d04058d87801e2b6bd7e5c7089 through before ff64c5bfef12461df8450e0f50bb693b5269c720 (git); 2.6.17; V3.1.6 through before * (custom) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.