CVE-2026-31780 wifi: wilc1000: fix u8 overflow in SSID scan buffer size calculation
An integer overflow in the Linux kernel's wilc1000 WiFi driver causes a heap buffer overflow, potentially allowing attackers to execute code or crash the system.
- 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-2026-31780?
CVE-2026-31780 is a high-severity vulnerability in Linux kernel, published on 1 May 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:
wifi: wilc1000: fix u8 overflow in SSID scan buffer size calculation
The variable valuesize is declared as u8 but accumulates the total length of all SSIDs to scan. Each SSID contributes up to 33 bytes (IEEE80211_MAX_SSID_LEN + 1), and with WILC_MAX_NUM_PROBED_SSID (10) SSIDs the total can reach 330, which wraps around to 74 when stored in a u8.
This causes kmalloc to allocate only 75 bytes while the subsequent memcpy writes up to 331 bytes into the buffer, resulting in a 256-byte heap buffer overflow.
Widen valuesize from u8 to u32 to accommodate the full range.
Weakness: CWE-787
Which versions are affected by CVE-2026-31780?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31780?
Apply the vendor's patch.
Is CVE-2026-31780 being exploited?
There is no known exploitation of CVE-2026-31780 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31780, DEBIAN-CVE-2026-31780, GHSA-hjw2-6262-hhr9, ROOT-OS-DEBIAN-11-CVE-2026-31780, ROOT-OS-UBUNTU-2204-CVE-2026-31780, ROOT-OS-UBUNTU-2404-CVE-2026-31780 and 1 more.