The Linux kernel netfilter nft_fib module had a flaw where the destination register for NFT_FIB_RESULT_OIFNAME was declared with a length of IFNAMSIZ (four 32-bit registers), but on lookup failures, only one register was zeroed, leaving the remaining three registers uninitialized. This stale stack data could be leaked to userspace by downstream expressions that read the full register span. Additionally, the NFTA_FIB_F_PRESENT flag was accepted for any result type but only wrote a single byte, leaving the rest of the declared span stale. The fix replaced the partial zeroing with a function that zeroes the entire IFNAMSIZ register and restricted the NFTA_FIB_F_PRESENT flag to only NFT_FIB_RESULT_OIF with a matching single-byte destination declaration.

This vulnerability can lead to leakage of uninitialized kernel stack memory to userspace, potentially exposing sensitive kernel data. The CVSS vector indicates local attack complexity and privileges required, with no confidentiality or integrity impact but an availability impact. There are no known exploits in the wild.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The description indicates the vulnerability has been resolved in the Linux kernel by proper initialization of the affected registers and restricting flag usage. Users should apply official Linux kernel updates once available to remediate this issue.