CVE-2026-90949 in Red Hat
Summary
by MITRE • 09/14/2026
A flaw was found in GIMP's PSP (Paint Shop Pro) file loader. When processing a compressed selection channel, a heap-based buffer overflow can occur due to a mismatch between the allocated buffer size and the amount of data decompressed. A remote attacker could exploit this vulnerability by crafting a malicious PSP file. Opening this file in GIMP could lead to a crash or arbitrary code execution.
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Analysis
by VulDB Data Team • 09/14/2026
The identified vulnerability resides within the Paint Shop Pro (PSP) image format loader component of GNU Image Manipulation Program, commonly known as GIMP. This specific flaw is triggered during the processing of compressed selection channels embedded within a PSP file structure. The core technical deficiency involves a critical mismatch between the size of the memory buffer allocated by the application and the actual volume of data produced after decompression operations are completed. When GIMP attempts to load such a malformed or maliciously crafted file, it allocates space based on pre-compressed metadata or header information rather than accounting for potential expansion during the decompression phase. This architectural oversight results in a heap-based buffer overflow condition where the application writes more data into the allocated memory region than was reserved by the system allocator.
From a technical perspective, this vulnerability is classified under Common Weakness Enumeration as CWE-120, which denotes Buffer Copy without Checking Size of Input. The exploitation vector relies on an attacker constructing a specially designed PSP file that contains compressed selection channel data with inflated decompression ratios or manipulated headers indicating smaller sizes than the actual uncompressed payload. When a user opens this malicious file within GIMP, the application's parsing logic proceeds to allocate memory based on the deceptive header values. As the decompression routine executes and expands the data beyond the allocated heap boundaries, it overwrites adjacent memory structures. This corruption of heap metadata or neighboring objects can lead to immediate program instability, manifesting as a denial of service through application crash, or more severely, allow for arbitrary code execution if an attacker successfully controls the overwritten memory contents to hijack control flow.
The operational impact of this vulnerability is significant due to the nature of GIMP's user base and typical usage patterns. While GIMP is primarily used locally by graphic designers and digital artists, it frequently processes images received from external sources such as email attachments, file-sharing platforms, or collaborative projects. A remote attacker can distribute a malicious PSP file through these channels without requiring any prior authentication or interaction beyond the victim opening the file in their image editor. The successful exploitation of this flaw could result in complete compromise of the user's system, allowing the execution of arbitrary commands with the privileges of the GIMP process. This poses a substantial risk to data confidentiality and integrity on affected workstations, particularly in environments where users routinely handle untrusted image assets from diverse origins.
Mitigation strategies for this vulnerability involve both immediate remediation steps and long-term defensive measures. The primary solution is to apply vendor-provided patches that update the PSP loader module to correctly validate decompressed buffer sizes against allocated memory limits before performing copy operations. Security teams should ensure that all instances of GIMP are updated to versions where this heap overflow has been addressed by upstream developers. In addition to patching, organizations can implement application whitelisting or sandboxing policies to restrict the execution capabilities of image processing software when handling files from untrusted sources. Furthermore, users should be educated on the risks associated with opening image files obtained from unknown entities and encouraged to verify file integrity using checksums where possible. Integrating static analysis tools into development pipelines can also help detect similar buffer management errors in future code updates, aligning with secure coding standards recommended by industry bodies such as OWASP for preventing memory corruption vulnerabilities.