EUVD-2026-31644
GHSA-66fw-g229-xchr
Severity by source
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
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
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
Lifecycle Timeline
3DescriptionCVE.org
A flaw has been found in Totolink A8000RU 7.1cu.643_b20200521. The impacted element is the function setL2tpServerCfg of the file /cgi-bin/cstecgi.cgi of the component Web Management Interface. Executing a manipulation of the argument enable can lead to os command injection. The attack can be executed remotely. The exploit has been published and may be used.
AnalysisAI
OS command injection in Totolink A8000RU router firmware 7.1cu.643_b20200521 allows remote unauthenticated attackers to execute arbitrary operating system commands by manipulating the 'enable' argument passed to the setL2tpServerCfg function in /cgi-bin/cstecgi.cgi. Publicly available exploit code exists (published on GitHub), though EPSS probability remains modest at 0.94% (76th percentile), and the issue is not currently listed in CISA KEV.
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the Totolink A8000RU to be running firmware 7.1cu.643_b20200521 with the Web Management Interface (/cgi-bin/cstecgi.cgi) reachable by the attacker and the setL2tpServerCfg handler accessible. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H) indicates network-reachable, low-complexity, unauthenticated exploitation with high impact on confidentiality, integrity, and availability - yielding a score of 8.9. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker who can reach the router's Web Management Interface - either via a WAN-exposed admin port or from within the LAN - sends a crafted HTTP request to /cgi-bin/cstecgi.cgi invoking setL2tpServerCfg with shell metacharacters in the 'enable' parameter, causing the injected commands to execute with the router's web process privileges (typically root on embedded Linux). With public PoC code already published on GitHub, the attacker can use it to drop a reverse shell, persist a backdoor in firmware-writable storage, or pivot to monitor and tamper with traffic transiting the router. |
| Remediation | No vendor-released patch identified at time of analysis - Totolink has not published a fixed firmware version in the available references, and the vendor advisory page (https://www.totolink.net/) should be monitored for an updated build superseding 7.1cu.643_b20200521. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours: inventory all Totolink A8000RU routers and identify those running firmware 7.1cu.643_b20200521. …
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External POC / Exploit Code
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