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CVE-2026-80800

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Last modified

CVE-2026-80800 is a vulnerability of currently unknown severity. 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.

Description

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).

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= d646960f7986fefb460a2b062d5ccc8ccfeacc3a, < b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e; >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a, < e18d044bab6d3d0280639098c3fe6621692cbfe2; >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a, < 65a0ec7783b06068dda6745dd689bf4a91ee64aa; >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a, < 1964addc8dd535a05d5d3b55b4d1ac19ae31aa65; >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a, < 389986fd79e4d43f971a03b512645a1bb63c982f; >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a, < e87527b506c40db9af528714b7b1240918eb80fc; >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a, < 22e5177ba1196a0b272a6a46c2575eb940a939c4; >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a, < 0cfbdb0e13ab5b0765d77f96af67eb879cbc9736; >= d646960f7986fefb460a2b062d5ccc8ccfeacc3a, < 55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8
LinuxLinux3.3

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-80800?
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).
How severe is CVE-2026-80800?
Severity scoring for CVE-2026-80800 is pending analysis.
How do I fix CVE-2026-80800?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST