CVE-2026-5853

Totolink A7100RU CGI cstecgi.cgi setIpv6LanCfg os command injection

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Published Apr 9, 2026 CVSS 4.0 · 9.3 Critical EPSS 13.7% KEV · Not listed
Description
A security vulnerability has been detected in Totolink A7100RU 7.4cu.2313_b20191024. Affected by this vulnerability is the function setIpv6LanCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Such manipulation of the argument addrPrefixLen leads to os command injection. The attack may be performed from remote. The exploit has been disclosed publicly and may be used.

Analysis

AI-generated

Technical impact

A flaw in the setIpv6LanCfg function of the cstecgi.cgi handler on Totolink A7100RU routers allows attackers to inject arbitrary operating system commands through manipulation of the addrPrefixLen argument. This results in remote code execution with the privileges of the CGI process, exposing the device to complete compromise of confidentiality, integrity, and availability. The vulnerability carries a CVSS score of 9.3, indicating a very high severity that should be addressed with priority.

Affected Systems

The vulnerability affects Totolink A7100RU routers running firmware version 7.4cu.2313_b20191024. The specific component at risk is the CGI interface located at /cgi-bin/cstecgi.cgi, which processes the setIpv6LanCfg command. Only devices running the affected firmware revision are vulnerable; newer or older firmware versions not explicitly listed are not confirmed to be impacted.

Risk and Exploitability

The flaw can be exploited remotely without authentication as the vulnerable CGI endpoint is publicly reachable. Public exploits have already been disclosed, and an EPSS score of 14% indicates a moderate likelihood of exploitation in the wild. The vulnerability is not listed in CISA's KEV catalog, but the combination of a high CVSS score, existing public exploits and remote access makes the risk substantial. An attacker can send a crafted HTTP request to the cstecgi.cgi endpoint, inject shell commands via the addrPrefixLen parameter, and gain full control over the router.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the latest firmware update from Totolink that fixes the command injection issue.
  • If an immediate update is not available, block external access to /cgi-bin/cstecgi.cgi or disable IPv6 LAN configuration through router ACLs or firewall rules.
  • For remaining exposure, monitor incoming traffic to the cstecgi.cgi endpoint for anomalous parameters and log attempts for further investigation.

Generated by OpenCVE AI on October 25, 2026 at 20:58 UTC.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Totolink a7100ru
Vendors & Products Totolink a7100ru
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}
Type Values Removed Values Added
Description A security vulnerability has been detected in Totolink A7100RU 7.4cu.2313_b20191024. Affected by this vulnerability is the function setIpv6LanCfg of the file /cgi-bin/cstecgi.cgi of the component CGI Handler. Such manipulation of the argument addrPrefixLen leads to os command injection. The attack may be performed from remote. The exploit has been disclosed publicly and may be used.
Title Totolink A7100RU CGI cstecgi.cgi setIpv6LanCfg os command injection
First Time appeared Totolink
Totolink a7100ru Firmware
Weaknesses CWE-77
CWE-78
CPEs cpe:2.3:o:totolink:a7100ru_firmware:*:*:*:*:*:*:*:*
Vendors & Products Totolink
Totolink a7100ru Firmware
References
Metrics cvssV2_0

{'score': 10, 'vector': 'AV:N/AC:L/Au:N/C:C/I:C/A:C/E:POC/RL:ND/RC:UR'}

cvssV3_0

{'score': 9.8, 'vector': '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'}

cvssV3_1

{'score': 9.8, 'vector': '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'}

cvssV4_0

{'score': 9.3, 'vector': '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'}
Weaknesses
  • CWE-77

    Improper Neutralization of Special Elements used in a Command ('Command Injection')

  • CWE-78

    Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Sources

Status
PUBLISHED
Assigner
VulDB
Published
Updated
Apr 9, 2026, 2:47 PM
Reserved
Apr 8, 2026, 7:20 PM

View source JSON

Updated
Apr 9, 2026, 2:47 PM

JSON

Status
Deferred
Published
Apr 9, 2026, 7:16 AM
Modified
Oct 26, 2026, 9:10 PM

View source JSON

No data.

Updated
Oct 25, 2026, 9:00 PM

JSON