CVE-2026-90947 in GIMP
Summary
by MITRE • 09/14/2026
A flaw was found in GIMP. When processing a specially crafted lighting preset file, the Lighting Effects filter does not properly validate the number of light sources. This can lead to an out-of-bounds write, corrupting memory. An attacker could exploit this by convincing a user to open a malicious preset file, potentially causing a crash or enabling arbitrary code execution.
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Analysis
by VulDB Data Team • 09/14/2026
The vulnerability identified in GIMP represents a critical security flaw within the Lighting Effects filter component, specifically triggered during the processing of specially crafted lighting preset files. This issue stems from an insufficient validation mechanism regarding the number of light sources defined within the input file structure. When the application parses these presets, it fails to enforce strict bounds checking on the array or data structures used to manage multiple light source parameters. Consequently, if a malicious actor provides a preset file that specifies a quantity of lights exceeding the allocated memory buffer size, the software attempts to write data beyond the boundaries of the intended memory region. This lack of proper input validation is a fundamental design error that allows for heap-based or stack-based out-of-bounds writes, depending on how the internal structures are laid out in memory during runtime execution.
From a technical perspective, this flaw aligns with Common Weakness Enumeration (CWE) categories such as CWE-787: Out-of-bounds Write and CWE-20: Improper Input Validation. The core issue lies not merely in reading data but in the application's failure to verify that the count of light sources corresponds to a safe, pre-allocated memory block before proceeding with initialization routines. In complex image processing software like GIMP, filters often involve significant computational overhead and dynamic memory allocation. When an out-of-bounds write occurs, it can overwrite adjacent memory structures, including function pointers, object headers, or control flow data. This corruption destabilizes the application's internal state and creates a potential vector for arbitrary code execution if the attacker can precisely craft the overflow to manipulate critical program counters or return addresses.
The operational impact of this vulnerability is severe due to its remote exploitability via social engineering tactics. An adversary does not need direct network access to leverage this flaw; instead, they only need to convince a user to open a maliciously crafted preset file within GIMP. This interaction model places the burden on end-user awareness and application sandboxing rather than perimeter defenses. If successfully exploited, the immediate consequence is typically an application crash due to segmentation faults or memory protection violations triggered by the operating system detecting illegal memory access. However, in more sophisticated exploitation scenarios where memory layout can be controlled through heap spraying techniques similar to those described in MITRE ATT&CK technique T1203: Exploitation for Client Execution, the attacker could achieve arbitrary code execution with the privileges of the user running GIMP. This would allow full compromise of the local system, including access to sensitive files, installation of persistent malware, or use as a pivot point for further network attacks.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. The primary solution involves updating GIMP to versions where this specific input validation logic has been corrected by developers. Until such updates are applied, users should exercise extreme caution when opening preset files from untrusted sources or generated by unknown third-party tools. Security administrators can also implement application whitelisting policies to restrict the execution of GIMP in high-security environments or enforce strict file type restrictions that prevent the loading of potentially dangerous plugin data formats. Furthermore, enabling memory protection mechanisms such as Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) on client systems can significantly raise the bar for successful exploitation by making it difficult for attackers to predict memory addresses required for code injection or return-oriented programming attacks. Long-term resilience requires integrating fuzzing tools into the development pipeline specifically targeting preset file parsers to automatically detect out-of-bounds conditions before they reach production releases, ensuring that all external inputs are rigorously validated against expected schema constraints and size limits.