EUVD-2026-58599
GHSA-94fh-fvrp-53c2
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 authentication; stack overflow achieves full device compromise with no scope change beyond the router itself.
Primary rating from Vendor (VulDB).
CVSS VectorVendor: VulDB
Lifecycle Timeline
5DescriptionCVE.org
A security flaw has been discovered in TOTOLINK A800R 4.1.2cu.5137_B20200730. The impacted element is the function setIpQosRules of the file /cgi-bin/cstecgi.cgi of the component firewall.so. The manipulation of the argument Comment results in stack-based buffer overflow. The attack can be executed remotely. The exploit has been released to the public and may be used for attacks.
AnalysisAI
Stack-based buffer overflow in TOTOLINK A800R firmware 4.1.2cu.5137_B20200730 allows remote low-privileged attackers to execute arbitrary code by supplying an oversized Comment argument to the setIpQosRules function via /cgi-bin/cstecgi.cgi. The flaw resides in firewall.so, the router's QoS firewall shared library, and can result in full device compromise including confidentiality, integrity, and availability loss. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The CVSS 4.0 vector specifies PR:L (low privileges required), confirming that an attacker must hold a valid authenticated session on the router's web interface before the vulnerability can be triggered. … 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) scores 7.4 High, reflecting network-reachable, low-complexity exploitation with all-high impact on the vulnerable system and no subsequent system scope change. … 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 CVE-2026-19811. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, conduct an inventory scan to identify all TOTOLINK A800R devices running firmware 4.1.2cu.5137_B20200730 or earlier in your environment and immediately segregate them from production network segments; escalate simultaneously to TOTOLINK technical support for emergency remediation guidance. …
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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
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