CVE-2025-12241: TOTOLINK A3300R · Stack-based Buffer Overflow
Affects TOTOLINK A3300RSource CVE Database V5
Not known to be exploited · CVSS 8.7 High.
Data as of 26 Oct 2026, 08:30 UTC
- EPSS
- 1.0% chance of exploitation in 30 days – higher than 63% 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 26 Oct 2026.
What to do
AI-suggested
1. Immediately identify all TOTOLINK A3300R devices running firmware version 17.0.0cu.557_B20221024 within the network. 2. Monitor vendor communications for official firmware patches addressing CVE-2025-12241 and apply updates promptly once available. 3. Until patches are released, restrict access to the router's management interface by implementing network segmentation and firewall rules limiting access to trusted IP addresses only. 4. Disable remote management features if not required to reduce exposure. 5. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of detecting exploitation attempts targeting the /cgi-bin/cstecgi.cgi endpoint or unusual POST requests with 'lang' parameters. 6. Conduct regular network traffic analysis to identify anomalous activities indicative of exploitation attempts. 7. Educate IT staff on the vulnerability details and encourage rapid incident response readiness. 8. Consider device replacement if firmware updates are not forthcoming or devices are no longer supported. These steps go beyond generic advice by focusing on immediate containment, monitoring, and vendor coordination specific to this vulnerability.
Description
A vulnerability was detected in TOTOLINK A3300R 17.0.0cu.557_B20221024. This impacts the function setLanguageCfg of the file /cgi-bin/cstecgi.cgi of the component POST Parameter Handler. The manipulation of the argument lang results in stack-based buffer overflow. It is possible to launch the attack remotely. The exploit is now public and may be used.