CVE-2026-43453

A flaw was found in the Linux kernel's netfilter component, specifically within the nft_set_pipapo module. The pipapo_drop() function performs a stack out-of-bounds read. This occurs when an argument is evaluated at the call site before the function body executes, leading to a read beyond the allocated rulemap array. This could potentially lead to information disclosure or system instability.

pipapo_drop() can read one element past the stack allocated rulemap array when processing the last pipapo field. The out of bounds value is evaluated as a function argument even though pipapo_unmap() would return early for the last field, which makes this a real stack OOB read confirmed by KASAN. For the CVSS the PR:L is used in the paranoid score because some systems delegate CAP_NET_ADMIN through namespaces or containers, although normal nftables rule management is administrator controlled. The issue is not network reachable and is triggered through local nftables set update or removal control plane operations rather than packet traffic. Impact is mainly low availability through KASAN or kernel fault on instrumented or hardened builds. Limited confidentiality is only a paranoid consideration because the primitive is a stack OOB read, but the patch context does not show a reliable data disclosure path, OOB write, UAF, arbitrary write, or privilege escalation.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.