Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_lookup: fix catchall element handling with inverted lookups nft_lookup_eval() decides whether a lookup matched (`found`) from the direct set lookup and priv->invert before falling back to the catchall element used by interval sets (e.g. nft_set_rbtree) for the open-ended default range. Since `found` is never recomputed after `ext` is replaced by the catchall lookup, inverted lookups (NFT_LOOKUP_F_INV, "!= @set") can wrongly match or wrongly skip the catchall element, producing the wrong verdict. Fold the catchall lookup into `ext` before computing `found`, matching the order already used by nft_objref_map_eval().
References6
- git.kernel.org/stable/c/0ab8880865f9678eb6174e72c1fc4712e44c745c
- git.kernel.org/stable/c/238c612357b5a25f03eacf356f95034f8551f218
- git.kernel.org/stable/c/65d35cb555f40529a9edc6bf4beaa3bee917f015
- git.kernel.org/stable/c/87ff022a58788ff4a25cf2c609b9abae418c9323
- git.kernel.org/stable/c/e6107a4c74b54cb33e3bce162a63048ae5a6b198
- git.kernel.org/stable/c/ef0c7d4b04a0e6ad175323c24bc84e11470dd79d
Metrics
- CVSS 3.1
-
9.1
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - EPSS — exploit probability
- 1% percentile: 48 · as of 11 November 2026
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.