EUVD-2026-58606
GHSA-8w2r-9wr9-7g8j
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, low complexity; PR:L because the CVSS 4.0 source vector confirms authentication required; scope unchanged as impact is confined to the router.
Primary rating from Vendor (VulDB).
CVSS VectorVendor: VulDB
Lifecycle Timeline
5DescriptionCVE.org
A weakness has been identified in TOTOLINK A800R 4.1.2cu.5137_B20200730. This affects the function UploadCustomModule of the file /cgi-bin/cstecgi.cgi of the component product.so. This manipulation of the argument File causes stack-based buffer overflow. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks.
AnalysisAI
Stack-based buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 allows network-accessible, low-privilege attackers to potentially execute arbitrary code by sending a crafted request to the UploadCustomModule function in /cgi-bin/cstecgi.cgi. A public proof-of-concept exploit is hosted on GitHub, materially raising practical risk beyond what the absence of a CISA KEV listing might suggest. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires network access to the TOTOLINK A800R's HTTP-based CGI management interface (/cgi-bin/cstecgi.cgi) and low-privilege authentication, as indicated by PR:L in the CVSS 4.0 vector - the attacker must hold valid credentials or an active low-privilege session on the device. … 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) reflects network-reachable exploitation with low complexity, low-privilege authentication, and high impact on confidentiality, integrity, and availability of the router itself. … 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 for this vulnerability. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all network devices to identify TOTOLINK A800R routers running firmware 4.1.2cu.5137_B20200730 or related 4.1.2cu versions; immediately disconnect any internet-facing instances and isolate to an air-gapped segment or remove from production. …
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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 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
Stack-based buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 enables remote code execution via the rout
Same weakness CWE-121 – Stack-based Buffer Overflow
View allSame technique Stack Overflow
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External POC / Exploit Code
Leaving vuln.today