CVE-2025-54364 in Knack
Summary
by MITRE • 08/20/2025
Microsoft Knack 0.12.0 allows Regular expression Denial of Service (ReDoS) in the knack.introspection module (issue 2 of 2).
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Analysis
by VulDB Data Team • 09/01/2025
The vulnerability identified as CVE-2025-54364 represents a regular expression denial of service flaw within Microsoft Knack version 0.12.0, specifically affecting the knack.introspection module. This issue falls under the broader category of denial of service attacks that exploit poorly constructed regular expressions to consume excessive computational resources. The vulnerability manifests when the system processes malformed input through the introspection functionality, which is commonly used for analyzing and examining application structures and components.
The technical implementation of this vulnerability stems from the use of inefficient regular expressions within the knack.introspection module that are susceptible to catastrophic backtracking patterns. When an attacker submits malicious input that matches these vulnerable regex patterns, the regular expression engine enters into a state where it performs exponential time complexity operations, leading to significant resource consumption and ultimately system unresponsiveness. This behavior aligns with the Common Weakness Enumeration classification for ReDoS vulnerabilities under CWE-1321, which specifically addresses the weakness of regular expressions that can be exploited to cause denial of service through excessive backtracking.
The operational impact of this vulnerability extends beyond simple service disruption, as it can potentially be leveraged by malicious actors to exhaust system resources and cause extended downtime for applications utilizing Microsoft Knack. The introspection module typically serves as a diagnostic and analysis tool within the application framework, making it a critical component that attackers may target to gain persistent access or cause broader system instability. The vulnerability affects the availability aspect of the system by allowing an attacker to consume CPU resources and memory, leading to performance degradation or complete service unavailability. This type of attack can be particularly damaging in production environments where system uptime and resource availability are critical for business operations.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization within the knack.introspection module to prevent malicious regular expressions from being processed. Security measures should include replacing vulnerable regular expressions with more efficient alternatives that do not exhibit catastrophic backtracking behavior. Additionally, implementing rate limiting and resource monitoring for the introspection functionality can help detect and prevent abuse of this vulnerability. The remediation process should involve thorough code review of the regular expression patterns used within the module, ensuring that they are optimized for performance and do not contain patterns that could lead to exponential execution times. Organizations should also consider implementing network-level protections and intrusion detection systems to monitor for potential exploitation attempts targeting this specific vulnerability. The ATT&CK framework categorizes this type of vulnerability under T1499.004 for Network Denial of Service, highlighting the importance of protecting against resource exhaustion attacks that target application-level functionality.