CVE-2005-2874 in CUPS
Summary
by MITRE
The is_path_absolute function in scheduler/client.c for the daemon in CUPS before 1.1.23 allows remote attackers to cause a denial of service (CPU consumption by tight loop) via a "..\.." URL in an HTTP request.
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Analysis
by VulDB Data Team • 06/29/2025
The vulnerability identified as CVE-2005-2874 resides within the Common Unix Printing System CUPS daemon implementation, specifically in the scheduler/client.c file where the is_path_absolute function fails to properly validate URL paths. This flaw affects CUPS versions prior to 1.1.23 and represents a classic example of inadequate input validation that can be exploited to cause significant system resource exhaustion. The vulnerability manifests when the daemon processes HTTP requests containing specially crafted "..\.." URL sequences that trigger an infinite loop within the path resolution logic, consuming excessive CPU cycles and ultimately leading to denial of service conditions.
The technical implementation of this vulnerability stems from the improper handling of path traversal sequences in the is_path_absolute function, which is designed to determine whether a given path is absolute. When the daemon encounters a URL containing "..\.." sequences, the function enters a tight loop where it continuously processes the same path components without proper termination conditions. This behavior directly maps to CWE-835, which describes the weakness of a loop with an endpoint that cannot be reached, resulting in an infinite loop that consumes system resources. The flaw exists because the function does not adequately sanitize or validate the input path before processing it, allowing maliciously constructed URLs to bypass normal path validation mechanisms.
The operational impact of this vulnerability extends beyond simple resource exhaustion to potentially compromise the availability of print services within a network environment. Attackers can exploit this weakness by sending crafted HTTP requests to the CUPS daemon, causing it to consume 100% CPU resources in the tight loop until the system becomes unresponsive or crashes. This denial of service condition affects legitimate users who require print services, as the daemon becomes unavailable to process legitimate print jobs. The vulnerability is particularly dangerous in environments where CUPS serves as a critical printing infrastructure component, as it can be leveraged to disrupt business operations and potentially impact other network services that depend on printing capabilities.
Mitigation strategies for CVE-2005-2874 should focus on immediate patch deployment to upgrade CUPS to version 1.1.23 or later, which contains the necessary fixes for the path traversal validation issue. Organizations should also implement network-level protections such as firewall rules that restrict access to CUPS ports and implement rate limiting on HTTP request processing to prevent exploitation. Additionally, monitoring systems should be configured to detect unusual CPU consumption patterns that may indicate exploitation attempts. From a defensive perspective, this vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates the importance of input validation controls as outlined in the OWASP Top Ten security principles. The remediation process should include comprehensive testing of the patched system to ensure that legitimate print functionality remains intact while addressing the specific path traversal vulnerability that enables the infinite loop behavior.