CVE-2026-13539: Wavlink WL-NU516U1-A POST Parameter wireless.cgi sub_407504 stack-based overflow

Vulnerability summary

CVE-2026-13539 is a high (CVSS 9.0) vulnerability in wavlink wl-nu516u1-a. EPSS estimates a 0.85% chance of exploitation in the next 30 days, higher than 57.8% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 29-06-2026
   PublishedVulnerability first disclosed.
2. 29-06-2026
   Last modifiedVulnerability information updated.

Description

A vulnerability was identified in Wavlink WL-NU516U1-A M16U1_V240425. The impacted element is the function sub_407504 of the file /cgi-bin/wireless.cgi of the component POST Parameter Handler. Such manipulation of the argument Guest_ssid leads to stack-based buffer overflow. The attack can be executed remotely. The exploit is publicly available and might be used. It is suggested to upgrade the affected component. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.

• 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).