CVE-2026-1686
Published: 30 January 2026
Summary
CVE-2026-1686 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Totolink A3600R Firmware. Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 46.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2026-1686 is a buffer overflow vulnerability affecting the Totolink A3600R router on firmware version 5.9c.4959. The issue resides in the setAppEasyWizardConfig function within the /lib/cste_modules/app.so library, where manipulation of the apcliSsid argument triggers the overflow. Associated with CWE-119 and CWE-120, it was published on 2026-01-30 and carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
An attacker with low privileges can exploit this vulnerability remotely over the network with low complexity and no user interaction required. Exploitation results in high impacts to confidentiality, integrity, and availability, potentially enabling arbitrary code execution on the device. A proof-of-concept exploit has been publicly released.
Advisories referenced on VulDB and a GitHub repository detail the vulnerability and provide exploit code, but no specific patches or mitigation steps are outlined in the available information.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-5027
Vulnerability details
A security flaw has been discovered in Totolink A3600R 5.9c.4959. This issue affects the function setAppEasyWizardConfig in the library /lib/cste_modules/app.so. Performing a manipulation of the argument apcliSsid results in buffer overflow. It is possible to initiate the attack remotely. The…
more
exploit has been released to the public and may be used for attacks.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Buffer overflow in router's configuration function enables remote arbitrary code execution from low privileges, directly facilitating public-facing application exploitation (T1190) and privilege escalation (T1068).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly prevents buffer overflow by requiring validation and bounds checking on the apcliSsid input argument in setAppEasyWizardConfig.
Requires timely identification, reporting, and remediation of the specific buffer overflow flaw via firmware patching or upgrades.
Implements memory protections such as stack canaries, ASLR, and DEP to block exploitation of the buffer overflow even if triggered.