CVE-2019-17402 in Exiv2
Summary
by MITRE
Exiv2 0.27.2 allows attackers to trigger a crash in Exiv2::getULong in types.cpp when called from Exiv2::Internal::CiffDirectory::readDirectory in crwimage_int.cpp, because there is no validation of the relationship of the total size to the offset and size.
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Analysis
by VulDB Data Team • 05/21/2025
The vulnerability identified as CVE-2019-17402 resides within the Exiv2 library version 0.27.2, a widely used C++ library for reading and writing image metadata. This flaw manifests as a heap-based buffer overflow that occurs during the processing of CRW (Canon Raw) image files, specifically when the library attempts to parse directory structures within these files. The vulnerability stems from inadequate input validation mechanisms that fail to properly verify the relationship between total file size parameters and offset measurements during metadata extraction processes.
The technical implementation of this vulnerability occurs in the types.cpp file where the Exiv2::getULong function is invoked without proper bounds checking. This function is subsequently called by Exiv2::Internal::CiffDirectory::readDirectory in crwimage_int.cpp, creating a chain of function calls that ultimately leads to memory corruption. The root cause lies in the absence of validation checks that would normally ensure the total size parameter remains within acceptable bounds relative to the file offset and size parameters. This lack of validation allows maliciously crafted CRW files to trigger memory access violations.
From an operational perspective, this vulnerability presents a significant risk to systems that process image files, particularly those handling user-uploaded content or automated image processing workflows. Attackers can exploit this flaw by crafting specially malformed CRW files that, when processed by applications using Exiv2, will cause the target application to crash or potentially execute arbitrary code. The crash behavior typically manifests as a segmentation fault or access violation, rendering the affected application unstable and potentially exploitable for more advanced attacks.
The vulnerability aligns with CWE-129, which addresses improper validation of array index values, and CWE-125, which covers out-of-bounds read conditions. From an adversary perspective, this vulnerability maps to ATT&CK technique T1203, which involves exploiting software vulnerabilities in applications, and T1059, which covers command and scripting interpreter usage. The attack surface is particularly broad given Exiv2's widespread adoption in various image processing applications, content management systems, and digital asset management platforms.
Mitigation strategies should prioritize immediate patching of affected systems to version 0.27.3 or later, which contains the necessary validation fixes. Organizations should implement input sanitization measures that validate file structure integrity before processing, particularly for user-uploaded content. Additional protective measures include deploying application sandboxing, implementing strict file format validation, and utilizing memory protection mechanisms such as stack canaries and address space layout randomization. Regular security audits of image processing pipelines and monitoring for abnormal application crashes will help detect exploitation attempts and provide early warning of potential attacks targeting this vulnerability.