CVE-2025-12239: TOTOLINK A3300R · Buffer Overflow
Affects TOTOLINK A3300RSource CVE Database V5
Not known to be exploited · CVSS 8.7 High.
Data as of 26 Oct 2026, 06:26 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: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
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), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
AI-suggested
1. Immediately identify and inventory all TOTOLINK A3300R routers running the affected firmware version 17.0.0cu.557_B20221024 within the network. 2. Monitor vendor channels closely for official patches or firmware updates addressing CVE-2025-12239 and apply them promptly once available. 3. Until patches are released, restrict access to the router management interface by implementing network segmentation and firewall rules to block inbound traffic to /cgi-bin/cstecgi.cgi endpoints from untrusted networks. 4. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of detecting exploit attempts targeting this vulnerability. 5. Disable or limit Dynamic DNS configuration features if not required, reducing the attack surface. 6. Conduct regular vulnerability scans and penetration tests focusing on router firmware versions and exposed services. 7. Educate network administrators on the risks and signs of exploitation to enable rapid incident response. 8. Consider deploying network-level anomaly detection to identify unusual router behavior indicative of compromise.
Description
A weakness has been identified in TOTOLINK A3300R 17.0.0cu.557_B20221024. The impacted element is the function setDdnsCfg of the file /cgi-bin/cstecgi.cgi. Executing manipulation can lead to buffer overflow. The attack may be performed from remote. The exploit has been made available to the public and could be exploited.