CVE-2026-80799 nfc: llcp: fix OOB read and u8 offset wrap in TLV parsers
An attacker can trigger out-of-bounds reads and infinite loops in the Linux kernel NFC LLCP TLV parser via crafted packets, leading to information disclosure or system crash.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80799?
CVE-2026-80799 is a vulnerability in Linux, published on 4 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
nfc: llcp: fix OOB read and u8 offset wrap in TLV parsers
nfc_llcp_parse_gb_tlv() and nfc_llcp_parse_connection_tlv() contain three related bugs in their TLV parsing loops:
1. 'offset' is declared u8 but tlv_array_len is u16. When TLV data advances offset past 255 it silently wraps to zero, causing infinite loops or double-processing of buffer data.
2. Before reading tlv[0] (type) and tlv[1] (length) there is no check that offset+2 <= tlv_array_len. A truncated TLV causes an OOB read of one byte past the buffer end.
3. After reading the length field, the value bytes are accessed without checking offset+2+length <= tlv_array_len. A crafted length=0xFF on a short buffer causes up to 255 bytes of OOB read past the buffer end.
Both functions are reachable without authentication via nfc_llcp_set_remote_gb() which feeds remote LLCP general bytes directly into nfc_llcp_parse_gb_tlv() with no additional validation.
Fix all three issues by widening offset from u8 to u16 and adding bounds checks for both the TLV header and value field before each access.
Which versions are affected by CVE-2026-80799?
How do I fix CVE-2026-80799?
Apply the vendor's patch.
Is CVE-2026-80799 being exploited?
There is no known exploitation of CVE-2026-80799 in the wild and no public exploit code.
Sources
Also known as AZL-99657, BELL-CVE-2026-80799, DEBIAN-CVE-2026-80799, GHSA-2vfp-4qhq-6rfc, UBUNTU-CVE-2026-80799.