Linux Kernel up to 7.2.0 NFC LLCP TLV Parser nfc_llcp_connect_sn out-of-bounds

CVSS Meta Temp Score
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7.0$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.0. It has been declared as critical. Affected is the function nfc_llcp_connect_sn of the component NFC LLCP TLV Parser. Such manipulation leads to out-of-bounds. This vulnerability is documented as CVE-2026-80800. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 7.2.0. Affected by this issue is the function nfc_llcp_connect_sn of the component NFC LLCP TLV Parser. The manipulation with an unknown input leads to a out-of-bounds vulnerability. Using CWE to declare the problem leads to CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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).

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-80800 since 08/26/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/04/2026).

Upgrading to version 5.10.267, 5.15.218, 6.1.185, 6.6.154, 6.12.106, 6.18.47, 7.1.11, 7.2.1 or 7.3-rc1 eliminates this vulnerability. Applying the patch b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e/e18d044bab6d3d0280639098c3fe6621692cbfe2/65a0ec7783b06068dda6745dd689bf4a91ee64aa/1964addc8dd535a05d5d3b55b4d1ac19ae31aa65/389986fd79e4d43f971a03b512645a1bb63c982f/e87527b506c40db9af528714b7b1240918eb80fc/22e5177ba1196a0b272a6a46c2575eb940a939c4/0cfbdb0e13ab5b0765d77f96af67eb879cbc9736/55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8 is able to eliminate this problem.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.267/5.15.218/6.1.185/6.6.154/6.12.106/6.18.47/7.1.11/7.2.1/7.3-rc1
Patch: b2ebdfe3d5b76e91f267a61cbc3f9a0e3f77071e/e18d044bab6d3d0280639098c3fe6621692cbfe2/65a0ec7783b06068dda6745dd689bf4a91ee64aa/1964addc8dd535a05d5d3b55b4d1ac19ae31aa65/389986fd79e4d43f971a03b512645a1bb63c982f/e87527b506c40db9af528714b7b1240918eb80fc/22e5177ba1196a0b272a6a46c2575eb940a939c4/0cfbdb0e13ab5b0765d77f96af67eb879cbc9736/55c68ac93e7dacc0f5f608b9c39dd4ff48cf28e8

Timelineinfo

08/26/2026 CVE reserved
09/04/2026 +9 days Advisory disclosed
09/04/2026 +0 days VulDB entry created
09/04/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-80800 (🔒)
GCVE (CVE): GCVE-0-2026-80800
GCVE (VulDB): GCVE-100-398936

Entryinfo

Created: 09/04/2026 18:25
Changes: 09/04/2026 18:25 (59)
Complete: 🔍
Cache ID: 216::103

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