{"id":"CVE-2026-80800","summary":"nfc: llcp: bound the connect_sn TLV walk to the skb","details":"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 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-\u003elen - 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-\u003edata[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).","modified":"2026-09-06T03:46:48.795896373Z","published":"2026-09-04T15:13:14.271Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80800.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0cfbdb0e13ab5b0765d77f96af67eb879cbc9736"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1964addc8dd535a05d5d3b55b4d1ac19ae31aa65"},{"type":"WEB","url":"https://git.kernel.org/stable/c/22e5177ba1196a0b272a6a46c2575eb940a939c4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/389986fd79e4d43f971a03b512645a1bb63c982f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/65a0ec7783b06068dda6745dd689bf4a91ee64aa"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e18d044bab6d3d0280639098c3fe6621692cbfe2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e87527b506c40db9af528714b7b1240918eb80fc"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80800.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80800"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a"},{"fixed":"b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e"},{"fixed":"e18d044bab6d3d0280639098c3fe6621692cbfe2"},{"fixed":"65a0ec7783b06068dda6745dd689bf4a91ee64aa"},{"fixed":"1964addc8dd535a05d5d3b55b4d1ac19ae31aa65"},{"fixed":"389986fd79e4d43f971a03b512645a1bb63c982f"},{"fixed":"e87527b506c40db9af528714b7b1240918eb80fc"},{"fixed":"22e5177ba1196a0b272a6a46c2575eb940a939c4"},{"fixed":"0cfbdb0e13ab5b0765d77f96af67eb879cbc9736"},{"fixed":"55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80800.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.3.0"},{"fixed":"5.10.267"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.218"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.185"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.154"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.106"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.47"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.11"}]},{"type":"ECOSYSTEM","events":[{"introduced":"7.2.0"},{"fixed":"7.2.1"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80800.json"}}],"schema_version":"1.9.0"}