{"id":"CVE-2026-80800","title":"nfc: llcp: bound the connect_sn TLV walk to the skb","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfc: llcp: bound the connect_sn TLV walk to the skb\n\nCommit 27256cdb290e (\"nfc: llcp: bound SNL TLV parsing to the skb and\nadd length checks\") fixed the unbounded TLV w…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e","Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < e18d044bab6d3d0280639098c3fe6621692cbfe2","Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 65a0ec7783b06068dda6745dd689bf4a91ee64aa","Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 1964addc8dd535a05d5d3b55b4d1ac19ae31aa65","Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 389986fd79e4d43f971a03b512645a1bb63c982f","Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < e87527b506c40db9af528714b7b1240918eb80fc","Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 22e5177ba1196a0b272a6a46c2575eb940a939c4","Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 0cfbdb0e13ab5b0765d77f96af67eb879cbc9736","Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8","Linux 3.3"],"published":"2026-09-04","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:43:53.425Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-80800","references":[{"url":"https://git.kernel.org/stable/c/b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e"},{"url":"https://git.kernel.org/stable/c/e18d044bab6d3d0280639098c3fe6621692cbfe2"},{"url":"https://git.kernel.org/stable/c/65a0ec7783b06068dda6745dd689bf4a91ee64aa"},{"url":"https://git.kernel.org/stable/c/1964addc8dd535a05d5d3b55b4d1ac19ae31aa65"},{"url":"https://git.kernel.org/stable/c/389986fd79e4d43f971a03b512645a1bb63c982f"},{"url":"https://git.kernel.org/stable/c/e87527b506c40db9af528714b7b1240918eb80fc"},{"url":"https://git.kernel.org/stable/c/22e5177ba1196a0b272a6a46c2575eb940a939c4"},{"url":"https://git.kernel.org/stable/c/0cfbdb0e13ab5b0765d77f96af67eb879cbc9736"},{"url":"https://git.kernel.org/stable/c/55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8"}],"tags":["cve.org"],"epss":0.00234,"epssPercentile":0.13287,"ingestedAt":"2026-10-19T09:16:01.529Z","slug":"CVE-2026-80800","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnfc: llcp: bound the connect_sn TLV walk to the skb\n\nCommit 27256cdb290e (\"nfc: llcp: bound SNL TLV parsing to the skb and\nadd length checks\") fixed the unbounded TLV walk in nfc_llcp_recv_snl(),\nand commit d8bd2dedbde5 (\"nfc: llcp: fix OOB read and u8 offset wrap in\nTLV parsers\") subsequently bounded nfc_llcp_parse_gb_tlv() and\nnfc_llcp_parse_connection_tlv(). One sibling parser sharing the same\npattern remains unbounded: nfc_llcp_connect_sn().\n\nnfc_llcp_connect_sn() walks a TLV list, reading a two-byte header\n(type, length) followed by length bytes of value, without checking that\nthe two header bytes or the declared length stay within the buffer. It\nreturns a pointer to a service name of up to 255 bytes that may point\npast the end of the skb; it is subsequently consumed by memcmp() in\nnfc_llcp_sock_from_sn(). In addition tlv_array_len was computed as\n\"skb->len - LLCP_HEADER_SIZE\" in size_t, so a CONNECT/CC frame shorter\nthan the LLCP header underflows to a huge length and the walk runs far\npast the buffer.\n\nnfc_llcp_connect_sn() is reachable from nfc_llcp_recv_connect() and\nnfc_llcp_recv_cc(), i.e. from received CONNECT and CC PDUs. A nearby\nNFC device can reach this without authentication; LLCP link activation\nhappens automatically after NFC-DEP, and the nfc_llcp_rx_skb()\ndispatcher applies no minimum-length guard.\n\nWalk the TLV list by pointer, bounded by skb_tail_pointer(skb), and\nvalidate each declared length before use, matching the approach already\nused for nfc_llcp_recv_snl(). Starting the walk at\n&skb->data[LLCP_HEADER_SIZE] against the tail pointer also removes the\nsize_t underflow for short frames.\n\nFound by 0sec automated security-research tooling (https://0sec.ai).\n\n## Affected\n\n- `Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e`\n- `Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < e18d044bab6d3d0280639098c3fe6621692cbfe2`\n- `Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 65a0ec7783b06068dda6745dd689bf4a91ee64aa`\n- `Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 1964addc8dd535a05d5d3b55b4d1ac19ae31aa65`\n- `Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 389986fd79e4d43f971a03b512645a1bb63c982f`\n- `Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < e87527b506c40db9af528714b7b1240918eb80fc`\n- `Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 22e5177ba1196a0b272a6a46c2575eb940a939c4`\n- `Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 0cfbdb0e13ab5b0765d77f96af67eb879cbc9736`\n- `Linux >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a < 55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8`\n- `Linux 3.3`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}