CVE-2025-12241
Published: 27 October 2025
Summary
CVE-2025-12241 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Totolink A3300R Firmware. Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 47.5% of CVEs by exploit likelihood; 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-2025-12241 is a stack-based buffer overflow vulnerability in the TOTOLINK A3300R router running firmware version 17.0.0cu.557_B20221024. The issue affects the setLanguageCfg function within the /cgi-bin/cstecgi.cgi file, specifically the POST Parameter Handler component, where manipulation of the 'lang' argument triggers the overflow. Associated with CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-121 (Stack-based Buffer Overflow), it 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).
The vulnerability enables remote exploitation by an attacker with low privileges, such as an authenticated user on the network. By sending a specially crafted POST request manipulating the 'lang' parameter, the attacker can overflow the stack, potentially leading to arbitrary code execution, data corruption, or denial of service, with high impacts on confidentiality, integrity, and availability.
Advisories from VulDB (ctiid.329911, id.329911, submit.673723) document the issue and note that an exploit is publicly available on GitHub at https://github.com/noahze01/IoT-vulnerable/blob/main/TOTOLink/A3300R/setLanguageCfg.md, increasing the risk of active use. The vendor's site at https://www.totolink.net/ provides general support resources, but no specific patch details are outlined in the provided references.
The exploit's public availability heightens the urgency for affected users to monitor and update firmware where possible.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-36127
Vulnerability details
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…
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attack remotely. The exploit is now public and may be used.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Stack-based buffer overflow in the router's web CGI interface (/cgi-bin/cstecgi.cgi) via POST parameter allows remote exploitation of a public-facing application.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates the CVE by identifying, reporting, and patching the stack-based buffer overflow flaw in the setLanguageCfg function.
Prevents exploitation by validating the 'lang' POST parameter to restrict operations within memory bounds and avoid buffer overflows.
Protects against stack-based buffer overflow leading to arbitrary code execution via memory safeguards like stack canaries and non-executable memory.