High

OS Command Injection in Totolink A7100RU setDmzCfg

IdentifiersCVE-2026-5975CWE-78· Improper Neutralization of Special…

CVE-2026-5975 is an OS command injection vulnerability affecting Totolink A7100RU firmware version 7.4cu.2313_b20191024. The flaw is in the setDmzCfg function within /cgi-bin/cstecgi.cgi, part of the device's CGI Handler. According to the provided content, improper handling of the wanIdx argument allows attacker-controlled input to reach an operating system command context, resulting in command injection. The issue is remotely exploitable, and the provided context states that a public exploit is available.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can allow a remote attacker to execute arbitrary operating system commands on the affected device. Based on the provided CVSS vectors and description, this can result in full compromise of confidentiality, integrity, and availability on the router, including unauthorized configuration changes, disruption of network services, and potential use of the device as a foothold for further activity.

Mitigation

If you can’t patch tonight, do this now.

Until a patch is available, restrict access to the affected CGI interface /cgi-bin/cstecgi.cgi to trusted administrative networks only, disable remote administration if not strictly required, and place the device management interface behind network-layer access controls such as firewall rules or VPN-only access. Monitor for suspicious requests targeting setDmzCfg or containing crafted wanIdx values, and consider isolating or replacing affected devices where exposure cannot be reduced.

Remediation

Patch, then assume compromise.

Upgrade to a vendor-fixed firmware version if one is available from Totolink. Because the provided content identifies the vulnerable version as 7.4cu.2313_b20191024 but does not specify a patched release, the exact fixed version is currently not available from the supplied information. Review vendor advisories and firmware release notes, and replace or retire the device if no supported fix is provided.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

TotolinkA7100ruhardware

TotolinkA7100ru Firmwareoperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

4 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

4 SOURCESView more in app

cvefeed high severityNews

Apr 9, 2026

CVE-2026-5975 - Totolink A7100RU CGI cstecgi.cgi setDmzCfg os command injection

A remote OS command injection vulnerability in the CGI Handler of Totolink A7100RU 7.4cu.2313_b20191024, specifically in the setDmzCfg function of /cgi-bin/cstecgi.cgi via the wanIdx argument.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3