CVE-2026-80798 nfc: llcp: reject PDUs shorter than the LLCP header
An attacker with nearby NFC access can trigger an out-of-bounds read in the Linux kernel LLCP handler, potentially causing a crash or leaking memory.
- 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-2026-80798?
CVE-2026-80798 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: reject PDUs shorter than the LLCP header
Every LLCP PDU begins with a two-byte header (DSAP/SSAP + PTYPE), but the receive path never checked that a frame is at least LLCP_HEADER_SIZE bytes before parsing it.
nfc_llcp_rx_skb() reads the header via nfc_llcp_ptype()/nfc_llcp_dsap()/ nfc_llcp_ssap(), which dereference pdu->data[0] and pdu->data[1], and a CONNECT or CC PDU then computes
tlv_array_len = skb->len - LLCP_HEADER_SIZE;
as a size_t and hands it to the TLV walk. When the frame is shorter than the header the subtraction wraps to a huge value and the walk runs far past the buffer, an out-of-bounds read.
A nearby NFC device can reach this without authentication; LLCP link activation happens automatically after NFC-DEP.
Guard the common receive choke point __nfc_llcp_recv(), shared by both the target (nfc_llcp_data_received()) and initiator (nfc_llcp_recv()) paths, so a short skb is dropped before the rx_work worker parses it. Use pskb_may_pull() rather than a skb->len test so the two header bytes are guaranteed to sit in the skb linear area even for a non-linear skb, matching how the sibling NCI and HCI receive paths validate their headers.
Reproduced with a KFENCE out-of-bounds read via /dev/virtual_nci on linux-next.
Found by 0sec automated security-research tooling (https://0sec.ai).
Which versions are affected by CVE-2026-80798?
How do I fix CVE-2026-80798?
Apply the vendor's patch.
Is CVE-2026-80798 being exploited?
There is no known exploitation of CVE-2026-80798 in the wild and no public exploit code.
Sources
Also known as AZL-99681, BELL-CVE-2026-80798, DEBIAN-CVE-2026-80798, GHSA-p65w-76hh-qj57, UBUNTU-CVE-2026-80798.