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The `acer_cgi.log` file on the Acer Wave 7 router is stored in the device’s firmware and can be retrieved via the web interface without any authentication. An attacker simply requests the file over HTTP, and the web server serves it directly because access controls are missing. Inside this log file, both the web administration password and the Telnet service password are written in cleartext. After downloading the file, the attacker extracts the credentials and uses them to log into the router’s admin panel or enable Telnet access. With Telnet access, the attacker can execute arbitrary system commands, change firewall rules, exfiltrate internal network data, or plant persistent backdoors. The vulnerability stems from two security failures: (1) improper file permissions that allow unauthenticated reads of a log file, and (2) the practice of storing sensitive credentials in cleartext within a world-readable log. Because the log file is created during normal device operation and is continuously appended, the credentials remain exposed until the file is deleted or its permissions are fixed. This issue affects all devices running firmware version T7c_GBL_1.01.000055 or earlier and is classified as CWE-532 (Insertion of Sensitive Information into Log File).
DailyCVE Form:
Platform: Acer Wave 7 Router
Version: T7c_GBL_1.01.000055 or earlier
Vulnerability: Unauthenticated plaintext credential exposure
Severity: Critical (CVSS 10.0)
date: 2026-05-29
Prediction: Patch expected by 2026-06-30
What Undercode Say:
Locate vulnerable targets via search engine inurl:acer_cgi.log Direct access to the log file curl http://192.168.76.1/acer_cgi.log Extract credentials from the log grep -E "username|password|login" acer_cgi.log Use extracted Telnet credentials telnet 192.168.76.1
Exploit:
- Reconnaissance – Identify Acer Wave 7 routers via Shodan or Google dorks (e.g.,
inurl:acer_cgi.log). - File retrieval – Send a GET request to `/acer_cgi.log` without any authentication headers.
- Credential extraction – Parse the plaintext lines containing `web_password=` and
telnet_password=. - Unauthorized access – Log in to the web admin interface using the extracted web credentials, or connect via Telnet using the extracted Telnet password.
- Full device takeover – Once logged in, modify firewall rules, disable logging, or install persistent malware.
Protection:
- Immediate mitigation (no patch yet): Disable remote management; block Internet access to port 80/443/TCP, 23/TCP from untrusted sources.
- Permanent fix: Apply the upcoming firmware update (expected end of June 2026) that restricts access to `acer_cgi.log` and removes plaintext credentials from log files.
- Defensive hardening: Disable Telnet entirely; use SSH instead; enforce strong, rotated admin passwords; enable HTTPS for the web interface.
Impact:
- Confidentiality – Complete loss of admin credentials, allowing an attacker to read all configuration data.
- Integrity – The attacker can modify routing tables, DNS settings, and security policies.
- Availability – The device could be bricked or turned into a botnet node.
- Lateral movement – Compromised router gives the attacker a foothold into the internal home/office network.
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Sources:
Reported By: nvd.nist.gov
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