CVE-2026-81893 in Red Hat
Summary
by MITRE • 08/27/2026
A flaw was found in gdk-pixbuf. When loading a specially crafted JPEG image containing chunked ICC profile markers, an error during ICC profile parsing can leave stale size metadata after the profile buffer is freed. A subsequent allocation in the same decode can cause an out-of-bounds write, potentially crashing the application. To exploit this flaw, an application using gdk-pixbuf must process the malicious JPEG image.
Affected version >= 2.26.4
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Analysis
by VulDB Data Team • 08/27/2026
The vulnerability identified within the gdk-pixbuf library represents a critical memory management error rooted in improper handling of International Color Consortium profile data during the parsing of JPEG images. This flaw specifically manifests when processing specially crafted JPEG files that contain chunked ICC profile markers, which are used to define color spaces and ensure consistent color reproduction across different devices. The core technical deficiency lies in the lifecycle management of internal buffers associated with these profiles. During the decoding process, if an error occurs while parsing the ICC profile data, the library fails to properly reset or clear certain size metadata fields before freeing the associated memory buffer. This oversight results in a state where the application retains references to stale size information that no longer corresponds to valid allocated memory regions.
This inconsistency creates a dangerous condition known as use-after-free with incorrect bounds checking. When the decoder proceeds to allocate new buffers for subsequent operations within the same image processing pipeline, it may rely on these corrupted metadata values to determine allocation sizes or write offsets. Consequently, this can lead to an out-of-bounds memory write operation. The attacker does not need direct system access but rather must trick a victim application that utilizes gdk-pixbuf into loading and rendering the malicious JPEG file. This could occur through various vectors such as opening the image in a gallery viewer, processing it within a web browser's image handling subsystem, or having it processed by an automated document conversion tool.
The operational impact of this vulnerability is primarily denial of service due to application crashes caused by memory corruption exceptions. While out-of-bounds writes can theoretically lead to arbitrary code execution if the attacker has precise control over heap layout and subsequent allocations, in the context of gdk-pixbuf's typical usage patterns for image decoding, immediate exploitation for remote code execution is less common than simple instability. However, the potential remains significant enough to classify this as a high-severity issue because it undermines the integrity of memory operations within widely deployed graphical toolkits. The vulnerability affects versions 2.26.4 and later, indicating that any system relying on these libraries for image processing is potentially exposed if they do not apply timely patches or mitigate exposure through input validation at higher application layers.
From a classification perspective, this flaw aligns with CWE-120 Buffer Copy without Checking Size of Input which describes the classic buffer overflow scenario where data is copied into a destination buffer without verifying that it fits within the allocated space. Additionally, because the root cause involves using memory after it has been freed and potentially reallocating based on stale state, it also relates to CWE-416 Use After Free. In terms of adversary tactics as defined by MITRE ATT&CK, this vulnerability facilitates initial access or execution phases where an attacker might use a crafted file to destabilize security software or gain foothold in systems that automatically process images from untrusted sources.
Mitigation strategies should focus on immediate patching and defensive programming practices. System administrators must update the gdk-pixbuf library to a version where this memory management logic has been corrected, ensuring that stale metadata is properly cleared upon error conditions. For developers integrating image processing capabilities, it is advisable to implement strict input validation before passing data to vulnerable libraries if updating is not immediately feasible. Furthermore, enabling security features such as Address Sanitizer during development and testing can help detect similar memory errors early in the software lifecycle. Organizations should also consider deploying application whitelisting or restricting file upload permissions for services that automatically process user-uploaded images to reduce the attack surface available to potential exploiters leveraging this specific parsing flaw.