CVE-2008-2935 in libxslt
Summary
by MITRE
Multiple heap-based buffer overflows in the rc4 (1) encryption (aka exsltCryptoRc4EncryptFunction) and (2) decryption (aka exsltCryptoRc4DecryptFunction) functions in crypto.c in libexslt in libxslt 1.1.8 through 1.1.24 allow context-dependent attackers to execute arbitrary code via an XML file containing a long string as "an argument in the XSL input."
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Analysis
by VulDB Data Team • 05/27/2025
The vulnerability identified as CVE-2008-2935 represents a critical heap-based buffer overflow in the libexslt library's cryptographic functions, specifically affecting the RC4 encryption and decryption operations. This flaw exists within the crypto.c file of libxslt versions ranging from 1.1.8 through 1.1.24, making it a widespread issue affecting numerous applications that rely on XML processing with cryptographic operations. The vulnerability stems from insufficient input validation and bounds checking in the exsltCryptoRc4EncryptFunction and exsltCryptoRc4DecryptFunction implementations, creating a dangerous condition where attacker-controlled data can overwrite adjacent memory regions.
The technical exploitation of this vulnerability occurs when an XML document containing a malformed XSL transformation with an excessively long string argument is processed by an application using the affected libxslt library. The RC4 cryptographic functions fail to properly validate the length of input strings before processing them, allowing attackers to supply strings that exceed the allocated buffer space. This buffer overflow can be leveraged to overwrite critical memory locations including return addresses, function pointers, or other control data, enabling arbitrary code execution. The context-dependent nature of this vulnerability means that successful exploitation requires a specific scenario where XML files with crafted malicious content are processed by vulnerable applications, though the attack surface is broad given the widespread use of libxslt in web applications, content management systems, and XML processing tools.
The operational impact of CVE-2008-2935 extends beyond simple code execution, as it can lead to complete system compromise when exploited against applications that process untrusted XML content. Applications using vulnerable libxslt versions are particularly at risk when handling user-uploaded XML files, web service requests, or any scenario where external XML data is transformed using XSLT templates. The vulnerability aligns with CWE-121, heap-based buffer overflow, and can be mapped to ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation typically results in arbitrary code execution that can be used to establish persistent access. Organizations running web servers, XML processing services, or any system that utilizes libxslt for XSLT transformations are potentially vulnerable, with the risk being particularly high for applications that do not properly validate or sanitize XML input.
Mitigation strategies for CVE-2008-2935 primarily involve upgrading to libxslt version 1.1.25 or later, where the buffer overflow conditions have been addressed through proper input validation and bounds checking. System administrators should also implement input sanitization measures, including limiting the length of strings processed by XSLT transformations and validating XML content before processing. Network segmentation and application whitelisting can reduce the attack surface by limiting which systems can process potentially malicious XML content. Additionally, implementing proper error handling and memory protection mechanisms such as stack canaries, address space layout randomization, and data execution prevention can help mitigate exploitation attempts, though these measures are secondary to the primary fix of upgrading the vulnerable library version. Organizations should also conduct comprehensive vulnerability assessments to identify all systems using affected libxslt versions and ensure that proper patch management procedures are in place to prevent future similar vulnerabilities.