GHSA-8PJC-RHHP-W5XQ

Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31
VLAI
Details

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).

Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-80800"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-04T16:18:06Z",
    "severity": null
  },
  "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\u0026skb-\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).",
  "id": "GHSA-8pjc-rhhp-w5xq",
  "modified": "2026-09-04T18:31:26Z",
  "published": "2026-09-04T18:31:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80800"
    },
    {
      "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.