Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: netfilter: reject zero shift in nft_bitwise Reject zero shift operands for nft_bitwise left and right shift expressions during initialization. The carry propagation logic computes the carry from the adjacent 32-bit word using BITS_PER_TYPE(u32) - shift. A zero shift operand turns this into a 32-bit shift, which is undefined behaviour. Reject zero shift operands in the control plane, alongside the existing check for values greater than or equal to 32, so malformed rules never reach the packet path.

Affected versions

Linux: 567d746b55bc66d3800c9ae91d50f0c5deb2fd93 through before 9baa08d6b6b096fad70049533f0d705d85fdc979 (git); 567d746b55bc66d3800c9ae91d50f0c5deb2fd93 through before 4fccea585631621c975883911a08d15b6671f7dc (git); 567d746b55bc66d3800c9ae91d50f0c5deb2fd93 through before 9ad26c272405f53834871cc2e46b9b5393a666c3 (git); 567d746b55bc66d3800c9ae91d50f0c5deb2fd93 through before bffef0acec9c3b837a785248a893137fb7f26c95 (git); 567d746b55bc66d3800c9ae91d50f0c5deb2fd93 through before ca24f1243ad1a4d12d6a23876bbbe3ed02099853 (git); 567d746b55bc66d3800c9ae91d50f0c5deb2fd93 through before 6f820139d16a4c9865a145d4a9cf9c92cc632c14 (git); 567d746b55bc66d3800c9ae91d50f0c5deb2fd93 through before f370205974f171a5868c13ff30d7642fed46e47b (git); 567d746b55bc66d3800c9ae91d50f0c5deb2fd93 through before fe11e5c40817b84abaa5d83bfb6586d8412bfd07 (git); 5.6; 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.