{"id":"CVE-2026-74579","title":"netfilter: nft_payload: fix mask build for partial field offload","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_payload: fix mask build for partial field offload\n\nnft_payload_offload_mask() builds the offload match mask for a payload\nexpression that covers only par…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 3ee7b3f813b11f28cd6efdf7f24d64b5a7fd4dc7","Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 8720df4504e0ed1781a702f65251bd47b3534d5e","Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 363c3a84a946d53e5e121c9f47c7c2b7d228c46b","Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < b19b5d2e042c294e2cc1c908dc598f9d64015396","Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < a375d8ace807767f29f276b681b6324c74929b1d","Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 16b553c46e347bc9de9946c4960654d5884a86de","Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 630295d5bba1d0e0f494cc459452eb0a0058c545","Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 39e88f28fb32bf02bd4b525c24c842c9cff5663d","Linux 5c2b4b4f9fa5b765b927e361e3d310bcb5773015","Linux >= 5.9.14 < 5.10","Linux 5.10"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-16T19:01:02.815654Z"},"published":"2026-08-17","updated":"2026-10-16","sourceUpdated":"2026-10-16T19:05:57.728Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74579","references":[{"url":"https://git.kernel.org/stable/c/3ee7b3f813b11f28cd6efdf7f24d64b5a7fd4dc7"},{"url":"https://git.kernel.org/stable/c/8720df4504e0ed1781a702f65251bd47b3534d5e"},{"url":"https://git.kernel.org/stable/c/363c3a84a946d53e5e121c9f47c7c2b7d228c46b"},{"url":"https://git.kernel.org/stable/c/b19b5d2e042c294e2cc1c908dc598f9d64015396"},{"url":"https://git.kernel.org/stable/c/a375d8ace807767f29f276b681b6324c74929b1d"},{"url":"https://git.kernel.org/stable/c/16b553c46e347bc9de9946c4960654d5884a86de"},{"url":"https://git.kernel.org/stable/c/630295d5bba1d0e0f494cc459452eb0a0058c545"},{"url":"https://git.kernel.org/stable/c/39e88f28fb32bf02bd4b525c24c842c9cff5663d"}],"tags":["cve.org"],"epss":0.0012,"epssPercentile":0.01706,"ingestedAt":"2026-10-16T19:46:24.340Z","slug":"CVE-2026-74579","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nft_payload: fix mask build for partial field offload\n\nnft_payload_offload_mask() builds the offload match mask for a payload\nexpression that covers only part of a header field.  For a partial IPv6\naddress match (field_len = 16, priv_len = 1) that shift is 1 << 120, which\nis undefined on the 32-bit int operand.  It also trims only one word, so\nthe remaining words stay 0xffffffff (and when priv_len is a multiple of 4\nthe trim is skipped entirely), leaving the mask covering more bytes than\nthe rule matches.\n\n  UBSAN: shift-out-of-bounds in net/netfilter/nft_payload.c:278:20\n  shift exponent 120 is too large for 32-bit type 'int'\n  ...\n\nThe match is byte-granular and struct nft_data is zero-initialised, so the\ncorrect mask is simply the first priv_len bytes set to 0xff. Set those\nbytes directly and drop the word/shift trimming; this removes the undefined\nshift and no longer over-masks the trailing bytes.\n\n## Affected\n\n- `Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 3ee7b3f813b11f28cd6efdf7f24d64b5a7fd4dc7`\n- `Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 8720df4504e0ed1781a702f65251bd47b3534d5e`\n- `Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 363c3a84a946d53e5e121c9f47c7c2b7d228c46b`\n- `Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < b19b5d2e042c294e2cc1c908dc598f9d64015396`\n- `Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < a375d8ace807767f29f276b681b6324c74929b1d`\n- `Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 16b553c46e347bc9de9946c4960654d5884a86de`\n- `Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 630295d5bba1d0e0f494cc459452eb0a0058c545`\n- `Linux >= a5d45bc0dc50f9dd83703510e9804d813a9cac32 < 39e88f28fb32bf02bd4b525c24c842c9cff5663d`\n- `Linux 5c2b4b4f9fa5b765b927e361e3d310bcb5773015`\n- `Linux >= 5.9.14 < 5.10`\n- `Linux 5.10`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}