CVE-2023-48631 in CSS-Tools
Summary
by MITRE • 12/14/2023
@adobe/css-tools versions 4.3.1 and earlier are affected by an Improper Input Validation vulnerability that could result in a denial of service while attempting to parse CSS.
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Analysis
by VulDB Data Team • 12/21/2023
The vulnerability identified as CVE-2023-48631 affects Adobe's css-tools library version 4.3.1 and earlier, representing a critical improper input validation flaw that can lead to denial of service conditions during CSS parsing operations. This issue resides within the library's handling of malformed or maliciously crafted CSS input, where insufficient validation mechanisms fail to properly sanitize or reject potentially harmful input sequences. The vulnerability manifests when the library attempts to process CSS content that contains unexpected or malformed structures, causing the parsing routine to enter an infinite loop or consume excessive computational resources.
The technical nature of this vulnerability falls under CWE-20, Improper Input Validation, which is a fundamental security weakness that occurs when software fails to properly validate or sanitize input data before processing. This particular implementation flaw in the css-tools library demonstrates how seemingly benign parsing operations can become vectors for resource exhaustion attacks. When the library encounters malformed CSS structures, the validation routines either fail to detect the anomaly or fail to handle it gracefully, leading to the system becoming unresponsive or consuming disproportionate CPU cycles during parsing attempts.
From an operational perspective, this vulnerability poses significant risks to applications that rely on Adobe's css-tools library for CSS processing, particularly in environments where user-supplied CSS content is accepted or when the library processes CSS from external sources. The denial of service impact can affect web applications, static site generators, CSS processing pipelines, and any system that depends on proper CSS parsing functionality. Attackers could exploit this vulnerability by submitting malicious CSS content that triggers the validation bypass, causing legitimate services to become unavailable or significantly degraded in performance, potentially affecting end-user experience and application availability.
The attack surface for this vulnerability extends across various deployment scenarios where the affected library is utilized, including web servers, content management systems, static site generators, and development tools that process CSS files. Organizations using versions 4.3.1 or earlier of the css-tools library should prioritize immediate remediation to prevent potential exploitation. The recommended mitigation strategy involves upgrading to version 4.3.2 or later, which includes enhanced input validation mechanisms and proper error handling for malformed CSS content. Additionally, implementing proper input sanitization at application layers that use this library can provide additional defense-in-depth measures, though the primary solution remains the library upgrade to address the root cause of the improper validation behavior.