CVE-2025-12240: TOTOLINK A3300R · Buffer Overflow
Affects TOTOLINK A3300RSource CVE Database V5
Public exploit available · CVSS 8.7 High.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 57% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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:PExploitation evidence
Disclosed: evidence found.
CVE published 27 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CVSS exploit maturity: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
- Immediately inventory all TOTOLINK A3300R devices and confirm firmware versions to identify affected units.
- Restrict access to the /cgi-bin/cstecgi.cgi endpoint by implementing firewall rules or network segmentation to limit exposure to trusted management networks only.
- Disable remote management interfaces if not strictly necessary, or enforce VPN access with strong authentication for remote administration.
- Monitor network traffic for unusual requests targeting the setDmzCfg function or anomalous CGI calls indicative of exploitation attempts.
- 6. Employ intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability once released. 7. Conduct regular security assessments and penetration tests focusing on router configurations and firmware vulnerabilities. 8. Educate IT staff on the risks of exposed router management interfaces and the importance of timely patching. 9. Maintain up-to-date asset inventories and vulnerability management processes to rapidly respond to emerging threats.
Description
A security vulnerability has been detected in TOTOLINK A3300R 17.0.0cu.557_B20221024. This affects the function setDmzCfg of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument ip leads to buffer overflow. It is possible to initiate the attack remotely. The exploit has been disclosed publicly and may be used.