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

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-03 · updated 2026-10-23
Weakness: CWE-119

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.

Affected products

Wavlink NU516U1: 708c073-mt7628

References

https://dl.wavlink.com/firmware/RD/WINSTAR_NU516U1-WO-A-2026-07-13-4b8a21f-mt7628-squashfs-sysupgrade.bin
https://github.com/oduoke567/WAVLINK-NU516U1-2026-05-1/blob/main/report2.md
https://vuldb.com/cve/CVE-2026-18588
https://vuldb.com/submit/850500
https://vuldb.com/vuln/385416
https://vuldb.com/vuln/385416/cti
https://vuldb.com/submit/850500

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