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Fencer Intel
medium 6.3

CVE-2025-4076 json

LB-LINK BL-AC3600 Password lighttpd.cgi easy_uci_set_option_string_0 command injection

published last yr. modified 4mo ago also EUVD-2025-12618

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
19.8%
EPSS 19.8% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

A vulnerability classified as critical has been found in LB-LINK BL-AC3600 up to 1.0.22. This affects the function easy_uci_set_option_string_0 of the file /cgi-bin/lighttpd.cgi of the component Password Handler. The manipulation of the argument routepwd leads to command injection. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. 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
partial
Assessed
last yr.

Exploit prediction

19.77% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/GrayLxton/BLink_poc referenced PoC, tagged "exploit" by a source, unverified
  • github.com https://github.com/GrayLxton/BLink_poc/blob/main/poc.py referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N
CNA 3.1 6.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
CNA 3.0 6.3 CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
CNA 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P
CNA 4.0 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/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

Affected products

  • LB-LINK BL-AC3600

Classification

Weakness
  • CWE-77 Improper Neutralization of Special Elements used in a Command
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component

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.