CVE-2026-82324 in Red Hat
Summary
by MITRE • 08/28/2026
A flaw was found in the file-iff (IFF/ILBM) plugin in GIMP. When processing a specially crafted IFF/ILBM image file, the plugin does not properly validate the HAM row size and improperly handles cases where the number of color planes (nPlanes) is zero. This causes a row size mismatch that bypasses memory bounds checking, resulting in heap out-of-bounds reads. This issue can result in an application crash, leading to a denial of service or a limited information disclosure of heap memory contents.
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Analysis
by VulDB Data Team • 08/28/2026
The vulnerability identified within the GIMP file-iff plugin represents a critical failure in input validation and bounds checking when processing IFF/ILBM image formats. As a widely used open-source raster graphics editor, GIMP relies on various plugins to handle diverse file types, including the legacy Interchange File Format (IFF) and its bitmap variant ILBM. The specific flaw resides in how the plugin interprets metadata associated with HAM (Hold And Modify) mode images. HAM is a color display technique that allows for high-color depth by storing only differences from previous pixels rather than full pixel data. This optimization requires precise calculation of row sizes based on the number of color planes and other structural parameters defined within the file header. The vulnerability arises because the plugin fails to adequately validate these critical dimensions, specifically neglecting proper checks against the HAM row size constraints and failing to handle edge cases where the number of color planes is zero.
From a technical perspective, the core issue is an improper handling of memory allocation and access boundaries driven by malformed input data. When a specially crafted IFF/ILBM file with manipulated header values is processed, the plugin calculates incorrect buffer sizes or offsets based on the flawed row size logic. This miscalculation leads to a heap out-of-bounds read operation. In C-based applications like GIMP, memory management relies heavily on explicit allocation and deallocation routines. When the application attempts to read pixel data from a location that exceeds the allocated heap segment due to this calculation error, it accesses memory regions outside its designated scope. This bypasses standard memory safety mechanisms because the vulnerability exploits logical errors in size computation rather than simple buffer overflow overwrites. The lack of validation for zero color planes further exacerbates the issue by allowing division-by-zero scenarios or undefined behavior that results in unpredictable pointer arithmetic and subsequent out-of-bounds access.
The operational impact of this vulnerability is primarily centered on application stability and potential information leakage. Since the exploit involves a read operation rather than a write, direct code execution via traditional buffer overflow techniques is not immediately feasible through this specific flaw alone. However, the immediate consequence is an application crash, which constitutes a denial-of-service condition for users attempting to open maliciously crafted image files. Beyond availability issues, heap out-of-bounds reads pose a significant risk of information disclosure. By reading memory contents outside the intended buffer boundaries, an attacker may potentially extract sensitive data stored in adjacent heap regions, such as pointers, cryptographic keys, or other user-specific information from previous operations within GIMP. This aligns with CWE-125 (Out-of-bounds Read), which describes situations where software reads past the end of a memory buffer, and CWE-369 (Divide By Zero), if the zero plane count leads to arithmetic errors affecting pointer calculations.
In terms of threat modeling and attack vectors, this vulnerability is classified under ATT&CK technique T1057 (Process Discovery) or more broadly as part of information gathering phases where an attacker seeks to leak memory contents for further exploitation or reconnaissance. It also falls under the broader category of CWE-20 (Improper Input Validation), highlighting the failure to sanitize and verify external data before processing. The risk is particularly acute given that GIMP users often process images from untrusted sources, such as downloads from the internet or emails containing image attachments. An attacker could distribute a malicious IFF/ILBM file designed specifically to trigger this heap out-of-bounds read when opened in GIMP, thereby compromising the integrity and confidentiality of the user's system environment through memory leakage or causing service disruption via crashes.
Mitigation strategies for this vulnerability involve both immediate patching by developers and defensive practices for end-users. The primary remediation is the application of vendor-supplied patches that update the file-iff plugin to include rigorous validation checks for HAM row sizes and explicit handling of zero color plane scenarios. Developers must ensure that all dimensional parameters extracted from image headers are validated against maximum allowable limits before being used in memory allocation or access routines. For users, it is advisable to keep GIMP updated to the latest stable version where such vulnerabilities have been addressed. Additionally, employing sandboxing techniques when opening files from untrusted sources can limit the potential impact of any successful exploitation attempts by isolating the application's memory space and restricting its ability to leak sensitive information to external entities or other processes on the host system.