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How the mentioned CVE works:
This vulnerability is an improper neutralization flaw (CWE-150) in Apache HTTP Server’s handling of Common Gateway Interface (CGI) programs. The server calculates and sets specific environment variables for CGI scripts it executes. However, a flaw allows environment variables defined in the Apache configuration files (e.g., via `SetEnv` or `PassEnv` directives) to unexpectedly override or supersede those server-calculated variables. An attacker can exploit this by crafting a malicious HTTP request that injects meta-characters or control sequences into headers or parameters that influence these configuration-based variables. When the CGI script runs, it receives the attacker-influenced environment variable instead of the correct, server-calculated one. This manipulation can alter the script’s execution path, leading to unintended behavior. The impact is limited to the context of the CGI process, potentially allowing for data tampering or limited information disclosure, but not direct remote code execution on the host server.
dailycve form:
Platform: Apache HTTP Server
Version: 2.4.0-2.4.65
Vulnerability: CGI environment override
Severity: Medium
date: 2025-12-05
Prediction: 2025-12-04
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Version Check Command: `httpd -v | grep “Apache/2.4″`
Configuration Review: Examine `httpd.conf` and included files for `SetEnv` or `PassEnv` directives used with CGI.
Upgrade Command (Example): `sudo apt update && sudo apt upgrade apache2`
How Exploit:
Mechanism: Attackers send crafted requests to influence environment variables passed from the Apache configuration to CGI scripts.
Goal: Alter the execution logic of a vulnerable CGI script to force unintended behavior.
Prerequisites: Requires a target server running a vulnerable Apache version (2.4.0-2.4.65) with CGI scripts enabled.
Protection from this CVE:
Primary Action: Upgrade Apache HTTP Server to version 2.4.66 or later.
Immediate Mitigation: If immediate upgrade is not possible, review and sanitize all `SetEnv` and `PassEnv` directives in configurations affecting CGI.
Long-term Security: Minimize use of CGI scripts in favor of more secure interfaces (e.g., native APIs, modern server-side frameworks).
Impact:
Confidentiality: Low risk of minor information disclosure.
Integrity: Low risk of data tampering within the CGI context.
Availability: No direct impact on server availability.
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Sources:
Reported By: nvd.nist.gov
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