Wavlink WL-NU516U1 login.cgi sub_404F68 cross site scripting

published 2026-03-15 7mo ago modified 2026-06-17 4mo ago also EUVD-2026-12208

cvss: 3.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits: 0; none known

A vulnerability was found in Wavlink WL-NU516U1 240425. The impacted element is the function sub_404F68 of the file /cgi-bin/login.cgi. The manipulation of the argument homepage/hostname results in cross site scripting. The attack can be launched remotely. The exploit has been made public and could be used. The vendor was contacted early about this disclosure.

Is CVE-2026-4166 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 7mo ago (2026-03-17)

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

github.com https://github.com/Litengzheng/vul_db/blob/main/WL-NU516U1/vul_15/README.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
CNA	3.1	3.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA	3.0	3.5	CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R
CNA	2.0	4.0	AV:N/AC:L/Au:S/C:N/I:P/A:N/E:POC/RL:ND/RC:UR
CNA	4.0	2.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA	3.1	3.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
CNA	2.0	4.0	AV:N/AC:L/Au:S/C:N/I:P/A:N

Affected products

Wavlink WL-NU516U1

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation
CWE-94 Improper Control of Generation of Code

References

github.com /Litengzheng/vul_db/blob/main/WL-NU516U1/vul_15/README.md
exploit
vuldb.com /?id.351073
vdb-entry, technical-description
vuldb.com /?ctiid.351073
signature, permissions-required
vuldb.com /?submit.769652
third-party-advisory
vuldb.com /?submit.769653
third-party-advisory
github.com /Litengzheng/vul_db/blob/main/WL-NU516U1/vul_14/README.md
related

Sources

CVE List CVE-2026-4166
NVD CVE-2026-4166

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

json all entries feed