CVE-2023-0645 in libjxl
Summary
by MITRE • 04/11/2023
An out of bounds read exists in libjxl. An attacker using a specifically crafted file could cause an out of bounds read in the exif handler. We recommend upgrading to version 0.8.1 or past commit https://github.com/libjxl/libjxl/pull/2101/commits/d95b050c1822a5b1ede9e0dc937e43fca1b10159 https://github.com/libjxl/libjxl/pull/2101/commits/d95b050c1822a5b1ede9e0dc937e43fca1b10159
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Analysis
by VulDB Data Team • 07/04/2025
The vulnerability CVE-2023-0645 represents a critical out of bounds read flaw within the libjxl library, which is a JPEG XL image format decoder used in various applications and systems. This issue specifically affects the EXIF handler component of the library, making it particularly dangerous as EXIF data is commonly embedded in digital images and is frequently processed by image handling software. The vulnerability arises when a maliciously crafted JPEG XL file is processed, triggering an unauthorized memory access pattern that extends beyond the allocated buffer boundaries.
This out of bounds read vulnerability falls under the CWE-125 category of "Out-of-Bounds Read" and represents a fundamental memory safety issue that can lead to various security consequences including information disclosure, application crashes, or potentially remote code execution depending on the execution context. The flaw occurs during the parsing of EXIF metadata within JPEG XL files, where insufficient input validation and boundary checking allows an attacker to manipulate the parsing logic to access memory locations that should remain protected. The vulnerability is particularly concerning because JPEG XL files are increasingly used in web applications, mobile platforms, and digital asset management systems where image processing occurs automatically.
The operational impact of this vulnerability extends beyond simple application instability to potential security breaches in systems that process untrusted image files. When exploited, the out of bounds read can expose sensitive memory contents including stack values, heap data, or other application secrets that might be stored in adjacent memory regions. This information disclosure can be leveraged by attackers to bypass security mechanisms, gather intelligence about the target system, or aid in further exploitation attempts. The vulnerability affects systems that rely on libjxl for image processing, including web browsers, image editing software, mobile applications, and server-side image handling services that process user-uploaded content.
Security practitioners should prioritize immediate remediation by upgrading to libjxl version 0.8.1 or applying the specific patch referenced in commit d95b050c1822a5b1ede9e0dc937e43fca1b10159 from the GitHub pull request. The fix implemented addresses the root cause by introducing proper bounds checking and input validation within the EXIF parsing logic, ensuring that all memory accesses remain within allocated buffer boundaries. Organizations should also consider implementing additional defensive measures such as input sanitization, sandboxing image processing components, and monitoring for suspicious file processing patterns. This vulnerability aligns with ATT&CK technique T1203 "Exploitation for Client Execution" and represents a common vector for privilege escalation attacks in image processing pipelines where untrusted input is processed without adequate security controls.