CVE-2026-80796 nfc: nci: add data_len bound checks to activation parameter extractors
A missing bounds check in the Linux kernel NFC driver allows attackers to read kernel memory or cause a crash via crafted NCI notifications.
- 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-2026-80796?
CVE-2026-80796 is a memory corruption 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: nci: add data_len bound checks to activation parameter extractors
nci_extract_activation_params_iso_dep() and nci_extract_activation_params_nfc_dep() read an inner length byte from the NCI RF_INTF_ACTIVATED_NTF payload and use it to memcpy() into fixed kernel buffers, but neither function receives the caller-validated activation_params_len. A crafted NCI notification with activation_params_len=1 and an inner length byte of up to 20 (NFC-A) or 50 (NFC-B) causes memcpy() to read that many bytes past the one valid byte in the activation params region -- a slab out-of-bounds read of kernel memory adjacent to the NCI skb.
The sibling nci_extract_rf_params_*() family was given equivalent protection by commit 571dcbeb8e63 ("net: nfc: nci: Fix parameter validation for packet data"), but the two activation parameter extractors were not updated at that time.
Add a data_len parameter to both functions, guard against an empty region before consuming the inner length byte, decrement the remaining count after consuming it, and clamp the copy length to what is actually available. Update both call sites to pass ntf.activation_params_len, which is already validated against the skb at ntf.c:801.
Which versions are affected by CVE-2026-80796?
How do I fix CVE-2026-80796?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-80796 being exploited?
There is no known exploitation of CVE-2026-80796 in the wild and no public exploit code.
Sources
Also known as AZL-99507, BELL-CVE-2026-80796, DEBIAN-CVE-2026-80796, GHSA-x2c2-6crc-q5ch, UBUNTU-CVE-2026-80796.