CVE-2025-12258
Published: 27 October 2025
Summary
CVE-2025-12258 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 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 45.1% 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-2025-12258 is a stack-based buffer overflow vulnerability affecting the TOTOLINK A3300R router on firmware version 17.0.0cu.557_B20221024. The flaw resides in the setOpModeCfg function within the /cgi-bin/cstecgi.cgi file, part of the POST Parameter Handler component. Exploitation occurs through manipulation of the "opmode" argument, as documented with 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) and mapped to CWEs CWE-119 and CWE-121. The vulnerability was published on 2025-10-27.
Attackers with low privileges (PR:L) can exploit this remotely (AV:N) with low attack complexity (AC:L) and no user interaction (UI:N). Successful exploitation grants high impacts across confidentiality, integrity, and availability (C:H/I:H/A:H), potentially enabling remote code execution via the buffer overflow.
Advisories and additional details, including a proof-of-concept, are available via VulDB entries (vuldb.com/?ctiid.329929, vuldb.com/?id.329929, vuldb.com/?submit.673725) and a GitHub repository (github.com/noahze01/IoT-vulnerable/blob/main/TOTOLink/A3300R/setOpModeCfg.md). The vendor website (www.totolink.net) should be consulted for any patches or firmware updates.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-36140
Vulnerability details
A vulnerability was detected in TOTOLINK A3300R 17.0.0cu.557_B20221024. Impacted is the function setOpModeCfg of the file /cgi-bin/cstecgi.cg of the component POST Parameter Handler. The manipulation of the argument opmode results in stack-based buffer overflow. The attack may be performed from…
more
remote.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The CVE describes a remotely exploitable stack-based buffer overflow in the public-facing web CGI interface (/cgi-bin/cstecgi.cg) of the TOTOLINK A3300R router via the 'opmode' POST parameter, directly enabling exploitation of a public-facing application.
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Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mitigates the CVE by requiring identification, reporting, and correction of the stack-based buffer overflow flaw through patching the affected firmware.
Requires validation of the 'opmode' POST parameter in the cstecgi.cgi handler to block malformed inputs causing the stack-based buffer overflow.
Implements memory safeguards like stack canaries, DEP, and ASLR to prevent exploitation of the stack-based buffer overflow for remote code execution.