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).
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).
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 04 Sep 2026 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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). | |
| Title | nfc: llcp: bound the connect_sn TLV walk to the skb | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-04T15:13:14.271Z
Reserved: 2026-08-26T14:34:25.793Z
Link: CVE-2026-80800
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-04T16:18:06.797
Modified: 2026-09-04T16:18:06.797
Link: CVE-2026-80800
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.