CVE-2026-46101
Published May 27, 2026
Modified May 27, 2026
Description
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.
References
Other References
https://git.kernel.org/stable/c/6f820139d16a4c9865a145d4a9cf9c92cc632c14
https://git.kernel.org/stable/c/bffef0acec9c3b837a785248a893137fb7f26c95
https://git.kernel.org/stable/c/ca24f1243ad1a4d12d6a23876bbbe3ed02099853
https://git.kernel.org/stable/c/f370205974f171a5868c13ff30d7642fed46e47b
https://git.kernel.org/stable/c/fe11e5c40817b84abaa5d83bfb6586d8412bfd07
Frequently Asked Questions
What is CVE-2026-46101? +
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.
How do I check if I'm vulnerable to CVE-2026-46101? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.