CVE-2022-29181 in macOS
Summary
by MITRE • 05/20/2022
Nokogiri is an open source XML and HTML library for Ruby. Nokogiri prior to version 1.13.6 does not type-check all inputs into the XML and HTML4 SAX parsers, allowing specially crafted untrusted inputs to cause illegal memory access errors (segfault) or reads from unrelated memory. Version 1.13.6 contains a patch for this issue. As a workaround, ensure the untrusted input is a `String` by calling `#to_s` or equivalent.
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Analysis
by VulDB Data Team • 07/23/2025
The vulnerability identified as CVE-2022-29181 affects Nokogiri, a widely-used Ruby library for processing XML and HTML documents. This security flaw resides within the XML and HTML4 SAX parsers implemented in versions prior to 1.13.6, creating a critical memory safety issue that can be exploited by malicious actors. The vulnerability stems from insufficient input validation mechanisms that fail to properly type-check all data entering these parsers, leaving the system susceptible to crafted malicious inputs that can trigger unpredictable memory access behaviors.
The technical nature of this vulnerability manifests as a lack of proper input sanitization within the SAX parser implementations, which allows attackers to supply malformed or specially crafted data that bypasses normal type checking procedures. When such untrusted inputs are processed, the parsers can attempt to access memory locations that they should not be permitted to reach, resulting in segmentation faults or unauthorized memory reads from adjacent memory regions. This behavior constitutes a classic buffer over-read condition that can potentially expose sensitive data or cause application crashes, representing a serious security risk for any system relying on Nokogiri for document processing.
From an operational standpoint, this vulnerability poses significant risks to applications that process untrusted XML or HTML content from external sources, including web applications, content management systems, and data processing platforms. The impact extends beyond simple application stability issues as the memory access errors could potentially be leveraged for information disclosure or denial of service attacks, making it particularly dangerous in production environments where these parsers handle user-generated content or external data feeds. The vulnerability's classification aligns with CWE-129, which addresses insufficient input validation, and may map to ATT&CK technique T1203 for legitimate code execution through memory corruption.
The remediation approach for this vulnerability involves upgrading to Nokogiri version 1.13.6 or later, which includes the necessary patch to address the type-checking deficiencies in the SAX parsers. Organizations should prioritize this upgrade as a critical security measure, particularly for systems processing external or untrusted data. Additionally, as a temporary workaround, developers can implement defensive programming practices by ensuring that all untrusted inputs are explicitly converted to String objects using methods like #to_s before processing, thereby forcing proper type handling within the parser. This approach helps mitigate the vulnerability until a full upgrade can be implemented, though it represents only a partial solution compared to the comprehensive fix provided in the patched version.