Bug 2464409 (CVE-2026-31780)

Summary: CVE-2026-31780 kernel: wifi: wilc1000: fix u8 overflow in SSID scan buffer size calculation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's wilc1000 Wi-Fi driver. An integer overflow vulnerability exists in the calculation of the SSID scan buffer size. This can lead to a heap buffer overflow when processing multiple Service Set Identifiers (SSIDs), potentially allowing a local attacker to cause a denial of service or execute arbitrary code.
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Description OSIDB Bzimport 2026-05-01 15:05:11 UTC 
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.
Comment 1 Keith Grant 2026-05-01 23:35:35 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050151-CVE-2026-31780-b92a@gregkh/T