CVE-2019-14294 in Xpdf
Summary
by MITRE
An issue was discovered in Xpdf 4.01.01. There is a use-after-free in the function JPXStream::fillReadBuf at JPXStream.cc, due to an out of bounds read.
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Analysis
by VulDB Data Team • 11/13/2023
The vulnerability identified as CVE-2019-14294 represents a critical use-after-free flaw within the Xpdf 4.01.01 document processing library, specifically within the JPXStream::fillReadBuf function located in JPXStream.cc. This issue arises from improper memory management during the processing of JPEG2000 encoded streams, creating a scenario where freed memory locations are accessed after being deallocated. The vulnerability manifests as an out-of-bounds read condition that can be exploited to execute arbitrary code or cause application crashes, fundamentally compromising the integrity and availability of systems utilizing this library.
The technical implementation of this flaw involves the JPXStream class's buffer management system where the fillReadBuf function fails to properly validate buffer boundaries before accessing memory locations. When processing malformed JPEG2000 streams, the function attempts to read beyond allocated memory boundaries, leading to the release of memory that subsequently gets accessed again. This memory access pattern creates a use-after-free condition classified under CWE-416, which represents the use of freed memory, and the out-of-bounds read scenario aligns with CWE-129, addressing improper validation of array indices. The vulnerability demonstrates a classic memory corruption issue where the application's memory management logic fails to properly track and validate buffer usage throughout the decoding process.
The operational impact of CVE-2019-14294 extends beyond simple application instability, creating potential security risks for systems that process untrusted document content. Attackers can craft malicious JPEG2000 streams that trigger the vulnerable code path, potentially leading to remote code execution in applications that utilize Xpdf for document rendering. This vulnerability affects any software ecosystem that depends on Xpdf for PDF and JPX document processing, including web browsers, document viewers, and enterprise content management systems. The exploitation of this flaw can result in complete system compromise, data exfiltration, or denial of service conditions that can be particularly devastating in enterprise environments where document processing is a core function.
Mitigation strategies for this vulnerability require immediate patching of affected Xpdf installations to version 4.01.02 or later, which contains the necessary memory management fixes. Organizations should implement strict input validation for all document processing pipelines, particularly when handling untrusted content from external sources. Security teams should consider deploying application whitelisting controls to restrict access to vulnerable applications and implement network segmentation to limit the potential attack surface. The ATT&CK framework categorizes this vulnerability under T1203 - Exploitation for Client Execution, highlighting the need for defensive measures including regular security assessments, memory safety checks, and monitoring for anomalous behavior in document processing applications. System administrators should also consider implementing sandboxing techniques and privilege separation to limit the potential impact of successful exploitation attempts.