Skip to main content
cve.nowby Sazabi
← All vulnerabilities
CVE-2026-80800

nfc: llcp: bound the connect_sn TLV walk to the skb

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.267, 5.15.218, 6.1.185, 6.6.154, 6.12.106, and 3 more
None on Exploit-DB, Metasploit or GitHub

Summary

In the Linux kernel, the following vulnerability has been resolved: nfc: llcp: bound the connect_sn TLV walk to the skb Commit 27256cdb290e ("nfc: llcp: bound SNL TLV parsing to the skb and add length checks") fixed the unbounded TLV walk in nfc_llcp_recv_snl(), and commit d8bd2dedbde5 ("nfc: llcp: fix OOB read and u8 offset wrap in TLV parsers") subsequently bounded nfc_llcp_parse_gb_tlv() and nfc_llcp_parse_connection_tlv(). One sibling parser sharing the same pattern remains unbounded: nfc_llcp_connect_sn(). nfc_llcp_connect_sn() walks a TLV list, reading a two-byte header (type, length) followed by length bytes of value, without checking that the two header bytes or the declared length stay within the buffer. It returns a pointer to a service name of up to 255 bytes that may point past the end of the skb; it is subsequently consumed by memcmp() in nfc_llcp_sock_from_sn(). In addition tlv_array_len was computed as "skb->len - LLCP_HEADER_SIZE" in size_t, so a CONNECT/CC frame shorter than the LLCP header underflows to a huge length and the walk runs far past the buffer. nfc_llcp_connect_sn() is reachable from nfc_llcp_recv_connect() and nfc_llcp_recv_cc(), i.e. from received CONNECT and CC PDUs. A nearby NFC device can reach this without authentication; LLCP link activation happens automatically after NFC-DEP, and the nfc_llcp_rx_skb() dispatcher applies no minimum-length guard. Walk the TLV list by pointer, bounded by skb_tail_pointer(skb), and validate each declared length before use, matching the approach already used for nfc_llcp_recv_snl(). Starting the walk at &skb->data[LLCP_HEADER_SIZE] against the tail pointer also removes the size_t underflow for short frames. Found by 0sec automated security-research tooling (https://0sec.ai).

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From d646960f7986fefb460a2b062d5ccc8ccfeacc3a · fixed in b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e; From d646960f7986fefb460a2b062d5ccc8ccfeacc3a · fixed in e18d044bab6d3d0280639098c3fe6621692cbfe2; From d646960f7986fefb460a2b062d5ccc8ccfeacc3a · fixed in 65a0ec7783b06068dda6745dd689bf4a91ee64aa; From d646960f7986fefb460a2b062d5ccc8ccfeacc3a · fixed in 1964addc8dd535a05d5d3b55b4d1ac19ae31aa65; From d646960f7986fefb460a2b062d5ccc8ccfeacc3a · fixed in 389986fd79e4d43f971a03b512645a1bb63c982f; From d646960f7986fefb460a2b062d5ccc8ccfeacc3a · fixed in e87527b506c40db9af528714b7b1240918eb80fc; From d646960f7986fefb460a2b062d5ccc8ccfeacc3a · fixed in 22e5177ba1196a0b272a6a46c2575eb940a939c4; From d646960f7986fefb460a2b062d5ccc8ccfeacc3a · fixed in 0cfbdb0e13ab5b0765d77f96af67eb879cbc9736; From d646960f7986fefb460a2b062d5ccc8ccfeacc3a · fixed in 55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8

  • Linux Linux

    3.3

  • KernelLinux

    From 3.3.0 · fixed in 5.10.267; From 5.11.0 · fixed in 5.15.218; From 5.16.0 · fixed in 6.1.185; From 6.2.0 · fixed in 6.6.154; From 6.7.0 · fixed in 6.12.106; From 6.13.0 · fixed in 6.18.47; From 6.19.0 · fixed in 7.1.11; From 7.2.0 · fixed in 7.2.1

References 9

git.kernel.org