CVE-2026-46101
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
In the Linux kernel, a vulnerability was found in the netfilter module where bitwise shift operations (nft_bitwise) did not reject a zero shift operand. This led to undefined behavior in the carry propagation logic, potentially causing incorrect operation or security breaches.
Risk Assessment
The organization may face system crashes or potential privilege escalation by sending a crafted network packet using a filtering rule with a zero bit shift.
Recommendation
Immediately update the Linux kernel to a version containing the fix that rejects zero shift operands in nft_bitwise expressions.
Original NVD description (English source)
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.