CVE-2014-2525 in Mac OS X
Summary
by MITRE
Heap-based buffer overflow in the yaml_parser_scan_uri_escapes function in LibYAML before 0.1.6 allows context-dependent attackers to execute arbitrary code via a long sequence of percent-encoded characters in a URI in a YAML file.
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Analysis
by VulDB Data Team • 05/09/2026
The vulnerability identified as CVE-2014-2525 represents a critical heap-based buffer overflow within the LibYAML library version 0.1.5 and earlier. This flaw exists in the yaml_parser_scan_uri_escapes function which processes percent-encoded characters within URIs found in YAML formatted files. The vulnerability manifests when the parser encounters excessively long sequences of percent-encoded characters, creating a condition where memory allocation calculations become insufficient to handle the input data, leading to memory corruption that can be exploited for arbitrary code execution.
The technical implementation of this vulnerability stems from inadequate bounds checking within the URI escape sequence parsing logic. When LibYAML processes a URI containing a long sequence of percent-encoded characters, the parser fails to properly validate the length of the decoded output buffer before writing data to memory. This flaw is classified as a heap-based buffer overflow under CWE-121, which specifically addresses buffer overflow conditions in heap memory allocations. The vulnerability requires context-dependent exploitation, meaning attackers must craft specific YAML files containing maliciously constructed URI escape sequences to trigger the overflow condition.
The operational impact of this vulnerability extends across numerous applications and systems that rely on LibYAML for parsing YAML formatted data. This includes configuration management tools, deployment frameworks, continuous integration systems, and various automation platforms that process user-provided YAML content. The remote code execution capability allows attackers to potentially compromise entire systems when these applications process untrusted YAML input, particularly in environments where YAML files are accepted from external sources or user uploads. The vulnerability aligns with ATT&CK technique T1059.006 for execution through scripting languages, as YAML processing often occurs within scripting environments where such vulnerabilities can be leveraged for broader system compromise.
Mitigation strategies for CVE-2014-2525 focus primarily on immediate library updates to version 0.1.6 or later, which contain proper bounds checking and memory allocation safeguards. Organizations should conduct comprehensive inventory assessments to identify all systems utilizing affected LibYAML versions and implement patch management procedures to ensure timely remediation. Additionally, input validation measures should be implemented at application layers to limit URI escape sequence lengths and prevent malformed YAML content from reaching the parser. Security monitoring should include detection of unusual YAML processing patterns and potential exploitation attempts targeting this vulnerability. The fix addresses the underlying CWE-121 issue by implementing proper buffer size calculations and memory allocation checks that prevent the overflow condition from occurring during URI escape sequence processing.