{"id":"CVE-2026-80800","state":"PUBLISHED","title":"nfc: llcp: bound the connect_sn TLV walk to the skb","description":"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->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).","publishedAt":"2026-09-04T15:13:14.271Z","updatedAt":"2026-10-19T08:43:53.425Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"e18d044bab6d3d0280639098c3fe6621692cbfe2","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"65a0ec7783b06068dda6745dd689bf4a91ee64aa","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"1964addc8dd535a05d5d3b55b4d1ac19ae31aa65","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"389986fd79e4d43f971a03b512645a1bb63c982f","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"e87527b506c40db9af528714b7b1240918eb80fc","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"22e5177ba1196a0b272a6a46c2575eb940a939c4","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"0cfbdb0e13ab5b0765d77f96af67eb879cbc9736","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/nfc/llcp_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.3","versionType":"semver"},{"version":"5.10.267","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.218","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.185","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.154","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.106","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.47","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.11","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2.1","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/nfc/llcp_core.c"]}],"references":["https://git.kernel.org/stable/c/b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e","https://git.kernel.org/stable/c/e18d044bab6d3d0280639098c3fe6621692cbfe2","https://git.kernel.org/stable/c/65a0ec7783b06068dda6745dd689bf4a91ee64aa","https://git.kernel.org/stable/c/1964addc8dd535a05d5d3b55b4d1ac19ae31aa65","https://git.kernel.org/stable/c/389986fd79e4d43f971a03b512645a1bb63c982f","https://git.kernel.org/stable/c/e87527b506c40db9af528714b7b1240918eb80fc","https://git.kernel.org/stable/c/22e5177ba1196a0b272a6a46c2575eb940a939c4","https://git.kernel.org/stable/c/0cfbdb0e13ab5b0765d77f96af67eb879cbc9736","https://git.kernel.org/stable/c/55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:07.220Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/80xxx/CVE-2026-80800.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80800","state":"PUBLISHED","datePublished":"2026-09-04T15:13:14.271Z","dateUpdated":"2026-10-19T08:43:53.425Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-26T14:34:25.793Z"},"containers":{"cna":{"title":"nfc: llcp: bound the connect_sn TLV walk to the skb","descriptions":[{"lang":"en","value":"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->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)."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"e18d044bab6d3d0280639098c3fe6621692cbfe2","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"65a0ec7783b06068dda6745dd689bf4a91ee64aa","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"1964addc8dd535a05d5d3b55b4d1ac19ae31aa65","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"389986fd79e4d43f971a03b512645a1bb63c982f","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"e87527b506c40db9af528714b7b1240918eb80fc","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"22e5177ba1196a0b272a6a46c2575eb940a939c4","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"0cfbdb0e13ab5b0765d77f96af67eb879cbc9736","versionType":"git"},{"version":"d646960f7986fefb460a2b062d5ccc8ccfeacc3a","status":"affected","lessThan":"55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/nfc/llcp_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.3","versionType":"semver"},{"version":"5.10.267","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.218","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.185","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.154","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.106","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.47","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.11","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2.1","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/nfc/llcp_core.c"]}],"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:43:53.425Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"5.10.267"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"5.15.218"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"6.1.185"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"6.6.154"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"6.12.106"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"6.18.47"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"7.1.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"7.2.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}