CVE-2026-31780
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Integer Overflow in Wilc1000 WiFi Driver Leading to Heap Buffer Overflow

Publication date: 2026-05-01

Last updated on: 2026-05-03

Assigner: kernel.org

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.
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Meta Information
Published
2026-05-01
Last Modified
2026-05-03
Generated
2026-05-07
AI Q&A
2026-05-01
EPSS Evaluated
2026-05-05
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux_kernel wifi From 0 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability exists in the Linux kernel's wifi component, specifically in the wilc1000 driver. It involves an overflow issue caused by the variable 'valuesize' being declared as an 8-bit unsigned integer (u8) but used to accumulate the total length of multiple SSIDs to scan.

Each SSID can be up to 33 bytes long, and with up to 10 SSIDs, the total length can reach 330 bytes. However, since 'valuesize' is a u8, it wraps around and only stores 74 instead of 330.

As a result, the kernel allocates only 75 bytes of memory but then copies up to 331 bytes into this buffer, causing a 256-byte heap buffer overflow. The fix involved changing 'valuesize' from u8 to u32 to correctly handle the full range of data.


How can this vulnerability impact me? :

This vulnerability can lead to a heap buffer overflow in the Linux kernel's wifi driver. Such an overflow can cause memory corruption, potentially leading to system crashes, instability, or allowing an attacker to execute arbitrary code with kernel privileges.

Exploitation of this vulnerability could compromise the security and stability of affected systems, especially those using the wilc1000 wifi driver.


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