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Fencer Intel
high 8.8

CVE-2026-4861 json

Wavlink WL-NU516U1 nas.cgi ftext stack-based overflow

published 7mo ago modified 4mo ago also EUVD-2026-16146

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 59%
public exploits
0
none known

Summary

A weakness has been identified in Wavlink WL-NU516U1 260227. This vulnerability affects the function ftext of the file /cgi-bin/nas.cgi. This manipulation of the argument Content-Length causes stack-based buffer overflow. The attack can be initiated remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
7mo ago

Exploit prediction

0.87% chance of exploitation in the next 30 days, higher than 59% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/Wlz1112/WAVLINK-NU516U1-V260227/blob/main/Content-Length.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
CNA 3.0 8.8 CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
CNA 2.0 9.0 AV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR
CNA 4.0 7.4 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 2.0 9.0 AV:N/AC:L/Au:S/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

Sources

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.