Wavlink WL-NU516U1 adm.cgi sub_406194 stack-based overflow

published 2026-02-16 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-7664

cvss: 7.2; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 46%
public exploits: 0; none known

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.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 8 mo ago (2026-02-17)

Exploit prediction

0.55% chance of exploitation in the next 30 days, higher than 46% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/Wlz1112/Wavlink-NU516U1-V251208-/blob/main/firmware_url.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.6	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
CNA	3.1	7.2	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
CNA	3.0	7.2	CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
CNA	2.0	8.3	AV:N/AC:L/Au:M/C:C/I:C/A:C/E:POC/RL:ND/RC:UR
CNA	4.0	7.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/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	7.2	CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CNA	2.0	8.3	AV:N/AC:L/Au:M/C:C/I:C/A:C

Affected products

Wavlink WL-NU516U1

Classification

Weakness

CWE-121 Stack-based Buffer Overflow
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

github.com /Wlz1112/Wavlink-NU516U1-V251208-/blob/main/firmware_url.md
exploit
vuldb.com /?id.346173
vdb-entry, technical-description
vuldb.com /?ctiid.346173
signature, permissions-required
vuldb.com /?submit.751908
third-party-advisory

Sources

CVE List CVE-2026-2566
NVD CVE-2026-2566

Fencer Vulns 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.

Summary