Sources: National Vulnerability Database, CVE.org, CISA KEV, FIRST EPSS
CVE-2026-121597 Overview
A weakness has been identified in TOTOLINK A950RG 4.1.2cu.5268_B20221104. This affects the function setAppEasyWizardConfig of the file /cgi-bin/cstecgi.cgi of the component Easy Setup Wizard Handler. Executing a manipulation of the argument functionType can lead to stack-based buffer overflow. The attack may be performed from remote. The exploit has been made available to the public and could be used for attacks.
Critical Impact
Affected Products
- TOTOLINK A950RG: see the vendor advisory for the exact affected versions
Discovery Timeline
- 2026-11-04: CVE-2026-121597 published to the National Vulnerability Database by cna@vuldb.com
- 2026-11-04: last updated in the NVD database
Technical Details for CVE-2026-121597
Vulnerability Analysis
CVE-2026-121597 is a Memory Buffer Errors weakness (CWE-119: Memory Buffer Errors, CWE-121: Stack Buffer Overflow) in TOTOLINK A950RG. Based on its CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction. The program reads or writes outside the memory it should.
With a CVSS base score of 8.6, apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Root Cause
The weakness is classified as CWE-119: Memory Buffer Errors, CWE-121: Stack Buffer Overflow. The program reads or writes outside the memory it should.
Attack Vector
Based on the CVSS vector, the flaw can be reached over the network, needs some level of access, and needs no user interaction. Attack complexity is low complexity.
No exploitation in the wild is confirmed by CISA at the time of the last update. Check the references below for any vendor or researcher proof of concept.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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
Detection Methods for CVE-2026-121597
Detection Strategies
- Inventory every instance of TOTOLINK A950RG and compare the running version with the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Run an authenticated vulnerability scan once your scanner ships a check for this CVE.
Monitoring Recommendations
- Forward TOTOLINK A950RG application, access and audit logs to your SIEM for retrospective hunting.
- Alert on new processes, configuration changes or outbound connections from the affected service.
- Track the vendor advisory and the CISA KEV catalog for changes in exploitation status.
How to Mitigate CVE-2026-121597
Immediate Actions Required
- Apply the fixed version of TOTOLINK A950RG named in the vendor advisory.
- Prioritize internet facing and business critical instances first.
- Rescan after the change to confirm the exposure is closed.
Patch Information
Use the fixed version listed in the vendor advisory for TOTOLINK A950RG.
Workarounds
- If patching must wait, restrict network access to the affected service and place it behind authentication or a web application firewall rule.
CWE References
- CWE-119: Memory Buffer Errors More CVEs with this weakness
- CWE-121: Stack Buffer Overflow More CVEs with this weakness
Technical References
This entry is built directly from NVD, CISA KEV and EPSS data. Verify fixed versions in the vendor advisory before you deploy.
Frequently asked questions
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