CVE-2026-90226 nfc: llcp: avoid userspace overflow on invalid optlen

Q: Is CVE-2026-90226 being exploited?

There is no known exploitation of CVE-2026-90226 in the wild and no public exploit code.

Not scored Published 17 Sep 2026 Updated 19 Oct 2026

A local attacker can trigger a buffer overflow in the Linux kernel NFC LLCP module via getsockopt, potentially leading to privilege escalation or code execution.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-90226?

CVE-2026-90226 is a memory corruption vulnerability in Linux, published on 17 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: avoid userspace overflow on invalid optlen

nfc_llcp_getsockopt() casts optval to (u32 __user *) for put_user(), so the kernel always stores 4 bytes regardless of the caller-supplied optlen. The existing min_t(u32, len, sizeof(u32)) only clamps the length reported back to userspace; it does not constrain the store. A call with optlen < 4 therefore writes past the user buffer, violating the getsockopt(2) contract for all five supported optnames.

Reject any call with optlen < sizeof(u32) up front. 'len' is int, so a plain size comparison would promote a negative optlen to size_t and slip past the check; an explicit 'len < 0' test is added first to catch negative values before the size compare.

Which versions are affected by CVE-2026-90226?

How do I fix CVE-2026-90226?

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-2026-90226 being exploited?