CVE-2026-23868 in giflib
Summary
by MITRE • 03/10/2026
Giflib contains a double-free vulnerability that is the result of a shallow copy in GifMakeSavedImage and incorrect error handling. The conditions needed to trigger this vulnerability are difficult but may be possible.
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Analysis
by VulDB Data Team • 04/23/2026
The vulnerability identified as CVE-2026-23868 resides within the giflib library, a widely used software component for handling gif image format processing in numerous applications and operating systems. This double-free vulnerability represents a critical memory corruption issue that can potentially lead to arbitrary code execution when exploited. The flaw manifests specifically within the GifMakeSavedImage function where improper handling of memory allocation and deallocation creates conditions for the same memory block to be freed twice, a scenario that fundamentally undermines the integrity of the heap management system. The vulnerability stems from a shallow copy operation that fails to properly duplicate all necessary data structures, combined with inadequate error handling mechanisms that allow the program to continue execution despite failed memory operations.
The technical implementation of this vulnerability involves a complex interplay between memory management routines and error propagation pathways within the giflib codebase. When processing certain malformed gif files, the GifMakeSavedImage function performs a shallow copy of image data structures without ensuring that all references are properly duplicated. This shallow copy approach means that multiple pointers may reference the same underlying memory location, creating a scenario where a subsequent error condition triggers a free operation on the same memory block that was already freed during the initial cleanup process. The conditions required to trigger this vulnerability are considered difficult to achieve in practice, as they require specific combinations of malformed input data and precise execution timing that would be challenging to reproduce consistently in real-world scenarios.
The operational impact of this vulnerability extends across numerous software ecosystems that rely on giflib for image processing capabilities. Applications including web browsers, image viewers, graphic design tools, and server-side image processing systems may be susceptible to exploitation if they incorporate vulnerable versions of giflib. The potential for arbitrary code execution represents a severe threat to system integrity and user security, as attackers could leverage this vulnerability to gain unauthorized access to affected systems. The difficulty of exploitation does not diminish the severity of the vulnerability, as the potential for successful exploitation increases when combined with other vulnerabilities or when attackers have the ability to control input data through web applications or file upload mechanisms. This vulnerability aligns with CWE-415 which specifically addresses double free conditions in software applications.
Mitigation strategies for CVE-2026-23868 require immediate attention from system administrators and software vendors who maintain installations of affected software. The primary remediation approach involves upgrading to patched versions of giflib that address the memory management issues within GifMakeSavedImage function through proper deep copying mechanisms and enhanced error handling protocols. Organizations should conduct comprehensive inventory assessments to identify all systems that utilize giflib or applications that may be vulnerable to this class of memory corruption issues. Network segmentation and input validation controls should be implemented as additional defensive measures, particularly for applications that process untrusted gif files from external sources. The vulnerability demonstrates characteristics consistent with ATT&CK technique T1203 which involves exploitation of memory corruption vulnerabilities to achieve privilege escalation or code execution within target systems. Regular security assessments and vulnerability scanning should be conducted to identify other potential memory corruption issues that may exist within similar image processing libraries and software components.