CVE-2026-18588: Wavlink WL-NU516U1 nas.cgi fgets stack-based overflow

Vulnerability summary

CVE-2026-18588 is a high (CVSS 10.0) vulnerability in wavlink wl-nu516u1_firmware. EPSS estimates a 1.10% chance of exploitation in the next 30 days, higher than 65.2% of scored vulnerabilities.

Timeline

1. 03-08-2026
   PublishedVulnerability first disclosed.
2. 03-08-2026
   Last modifiedVulnerability information updated.

Description

A vulnerability has been found in Wavlink WL-NU516U1 708c073-mt7628. This affects the function fgets of the file nas.cgi. The manipulation of the argument CONTENT_LENGTH leads to stack-based buffer overflow. Remote exploitation of the attack is possible. You should 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).