Totolink A7100RU CGI cstecgi.cgi setTelnetCfg os command injection

published 2026-04-10 7 mo ago modified 2026-10-26 13 d ago also EUVD-2026-21270

cvss: 9.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.8%; EPSS 1.8% chance of exploitation in 30 days, percentile 79%
public exploits: 0; none known

A security flaw has been discovered in Totolink A7100RU 7.4cu.2313_b20191024. This issue affects the function setTelnetCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Performing a manipulation of the argument telnet_enabled results in os command injection. The attack is possible to be carried out remotely. The exploit has been released to the public and may be used for attacks.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: total
Assessed: 6 mo ago (2026-04-10)

Exploit prediction

1.84% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/Litengzheng/vuldb_new/blob/main/A7100RU/vul_166/README.md referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	9.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P
CNA	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
CNA	3.0	9.8	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:R
CNA	2.0	10.0	AV:N/AC:L/Au:N/C:C/I:C/A:C/E:POC/RL:ND/RC:UR
CNA	4.0	8.9	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/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	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA	2.0	10.0	AV:N/AC:L/Au:N/C:C/I:C/A:C

Affected products

Totolink A7100RU

Classification

Weakness

CWE-78 Improper Neutralization of Special Elements used in an OS Command
CWE-77 Improper Neutralization of Special Elements used in a Command

References

github.com /Litengzheng/vuldb_new/blob/main/A7100RU/vul_166/README.md
exploit
vuldb.com /vuln/356548
vdb-entry, technical-description
vuldb.com /vuln/356548/cti
signature, permissions-required
vuldb.com /submit/792042
third-party-advisory
totolink.net /
product

Sources

CVE List CVE-2026-5994
NVD CVE-2026-5994

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