CVE-2019-14292 in Xpdf
Summary
by MITRE
An issue was discovered in Xpdf 4.01.01. There is an out of bounds read in the function GfxPatchMeshShading::parse at GfxState.cc for typeA!=6 case 1.
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Analysis
by VulDB Data Team • 11/13/2023
The vulnerability identified as CVE-2019-14292 represents a critical out-of-bounds read flaw within the Xpdf 4.01.01 document processing library. This issue manifests specifically within the GfxPatchMeshShading::parse function located in the GfxState.cc source file, where the software fails to properly validate input data when processing certain shading types. The vulnerability occurs in the context of typeA != 6 case 1, indicating that the flaw is triggered when the software encounters a particular shading parameter configuration that deviates from the expected norm. This type of vulnerability falls under the category of memory safety issues that can lead to unpredictable behavior and potential exploitation by malicious actors.
The technical nature of this flaw stems from insufficient bounds checking during the parsing of patch mesh shading data structures within PDF documents. When the GfxPatchMeshShading::parse function processes shading information, it does not adequately verify array boundaries or validate the range of indices used to access memory locations. This allows an attacker to craft a malicious PDF document containing specially crafted shading parameters that cause the application to read memory beyond the allocated buffer boundaries. Such out-of-bounds memory access can result in information disclosure, application crashes, or potentially more severe consequences depending on the execution context and memory layout. The vulnerability is particularly concerning because it can be triggered through normal document processing operations without requiring special privileges or complex attack vectors.
The operational impact of this vulnerability extends beyond simple application instability to potentially enable more sophisticated attack scenarios. When exploited, the out-of-bounds read can expose sensitive memory contents including stack data, heap information, or other internal application state that may contain credentials, encryption keys, or other confidential information. The vulnerability affects any system running Xpdf 4.01.01 that processes PDF documents, making it a widespread concern across various platforms and applications that depend on this library. This includes web browsers, document viewers, and server applications that handle PDF rendering. The potential for remote code execution cannot be entirely ruled out, particularly in environments where the application has elevated privileges or where the memory corruption could be leveraged in combination with other vulnerabilities, aligning with ATT&CK technique T1059.007 for remote code execution through memory corruption.
Mitigation strategies for CVE-2019-14292 should prioritize immediate software updates to versions that contain the patched implementation of the GfxPatchMeshShading::parse function. System administrators should implement comprehensive patch management procedures to ensure all affected systems receive the necessary security updates. Additionally, organizations should consider implementing defensive measures such as input validation controls, sandboxing mechanisms, and network segmentation to limit the potential impact of exploitation attempts. The vulnerability demonstrates the importance of proper bounds checking and input validation as outlined in CWE-129 and CWE-131, which specifically address issues related to insufficient bounds checking in memory operations. Security monitoring should also include detection of unusual memory access patterns and potential exploitation attempts that could indicate active exploitation of this vulnerability.