EUVD-2026-58735
GHSA-crrc-f7mf-5xhm
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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
Network-reachable CGI endpoint requires low-privilege auth (PR:L per CVSS 4.0); no complexity or prerequisites; full CIA impact on the router; no scope change as compromise is self-contained to the device.
Primary rating from Vendor (VulDB).
CVSS VectorVendor: VulDB
Lifecycle Timeline
5DescriptionCVE.org
A vulnerability was identified in TOTOLINK A800R 4.1.2cu.5137_B20200730. This impacts the function setUrlFilterRules of the file /cgi-bin/cstecgi.cgi of the component firewall.so. The manipulation of the argument url leads to stack-based buffer overflow. The attack can be initiated remotely. The exploit is publicly available and might be used.
AnalysisAI
Stack-based buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 enables remote code execution via the router's firewall URL-filtering CGI endpoint. An attacker holding low-privileged credentials can submit a crafted HTTP request to /cgi-bin/cstecgi.cgi targeting the setUrlFilterRules function; an oversized url argument overflows a fixed stack buffer in firewall.so, allowing arbitrary code execution - likely as root on the embedded MIPS platform. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires network-level reachability to the TOTOLINK A800R's HTTP or HTTPS management interface - typically port 80 or 443 on the LAN interface, or the WAN interface if remote management is enabled. … 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:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N) characterizes this as a straightforward remote exploitation path: no complexity, no attack prerequisites, no user interaction, full CIA triad impact on the vulnerable system. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | No vendor-released patch has been identified at time of analysis - the absence of a TOTOLINK advisory means organizations cannot rely on an official fix being available. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all TOTOLINK A800R devices in inventory and document which are running firmware 4.1.2cu.5137_B20200730 or earlier versions; assess whether low-privilege accounts (standard user credentials) can access the router's web console or API from internal networks. …
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Stack-based buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 allows remote low-privileged attackers to
Stack-based buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 allows network-accessible, low-privilege a
Stack-based buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 allows authenticated remote attackers to a
Stack-based buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 enables remote low-privileged attackers to
Stack-based buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 allows remote low-privileged attackers to
Buffer overflow in Totolink A800R router firmware 4.1.2cu.5137_B20200730 allows authenticated remote attackers to achiev
Same weakness CWE-121 – Stack-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
Leaving vuln.today