CVE-2026-2566: Wavlink WL-NU516U1 adm.cgi sub_406194 stack-based overflow

Vulnerability summary

CVE-2026-2566 is a high (CVSS 8.6) vulnerability in wavlink wl-nu516u1_firmware. EPSS estimates a 0.99% chance of exploitation in the next 30 days, higher than 62.1% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 16-02-2026
   PublishedVulnerability first disclosed.
2. 23-02-2026
   Last modifiedVulnerability information updated.

Description

A security vulnerability has been detected in Wavlink WL-NU516U1 up to 130/260. This affects the function sub_406194 of the file /cgi-bin/adm.cgi. Such manipulation of the argument firmware_url leads to stack-based buffer overflow. The attack can be launched remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferThe product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
• CWE-121Stack-based Buffer OverflowA stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).