CVE-2005-0595: BadBlue ext.dll buffer overflow via mfcisapicommand parameter

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 19 September 2026. Confidence: medium.

high priorityThe flaw is remotely exploitable without authentication, public exploit code exists, and EPSS is very high, though the product is legacy and no KEV listing is present.

What it is

BadBlue 2.55 contains a buffer overflow in ext.dll reachable through a long mfcisapicommand parameter. A remote, unauthenticated attacker can send a crafted request that overflows the buffer and may lead to arbitrary code execution on the web server. The flaw is old but the affected product is a network-facing web server, so any exposed instance is at risk.

Impact

Successful exploitation lets a remote attacker run arbitrary code with the privileges of the BadBlue service, potentially taking full control of the host. Even without code execution, the overflow can crash the service, causing denial of service.

Attack surface

The flaw is reached over the network through HTTP requests to the BadBlue web server, specifically via the mfcisapicommand parameter handled by ext.dll. The CVSS vector AV:N/AC:L/Au:N indicates no authentication and no user interaction are required.

Exploitation

CISA KEV does not list this CVE, but EPSS is high at roughly 0.60 (99th percentile) and multiple references are tagged Exploit, indicating public exploit code exists. No ransomware group is documented as using it.

What to do

• Apply the vendor patch referenced in the Secunia advisory and Full Disclosure post, or upgrade BadBlue to a fixed release.
• If no patch can be applied, remove or disable the ext.dll ISAPI extension and block requests containing mfcisapicommand.
• Restrict network access to the BadBlue service so only trusted hosts can reach it, and place it behind a filtering reverse proxy.
• Monitor and restart the service on crash, and treat repeated crashes as a possible exploitation attempt.

Detection

• Inspect web server logs for requests with unusually long or malformed mfcisapicommand parameter values.
• Alert on requests to ext.dll or ISAPI endpoints from unexpected source addresses.
• Watch for BadBlue service crashes or restarts that correlate with inbound HTTP traffic.
• Use network IDS signatures for the known exploit pattern against ext.dll.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.