CVE-2026-82328 in Red Hat
Summary
by MITRE • 08/28/2026
A flaw was found in the file-ico plugin in GIMP. When processing a specially crafted ICO image file, the plugin does not properly validate the used_clrs (palette count) parameter. This incorrect validation leads to improper memory bounds checking, resulting in a heap out-of-bounds read. 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 file-ico plugin for GIMP represents a critical failure in input validation and memory management during the processing of Icon image files. Specifically, the flaw resides in the handling of the used_clrs parameter, which indicates the number of colors defined in the icon's palette. When an attacker provides a specially crafted ICO file where this parameter is manipulated to exceed valid bounds or contains inconsistent values relative to the actual data size, the plugin fails to perform adequate checks before accessing memory buffers associated with that palette. This lack of rigorous validation allows the application to proceed with operations that assume safe access limits, thereby bypassing standard safety mechanisms designed to prevent unauthorized memory interactions.
From a technical perspective, this misconfiguration leads directly to a heap out-of-bounds read condition. In C-based applications like GIMP, which rely heavily on manual memory management, such errors occur when the program attempts to read data from a memory location that lies outside the allocated region of a heap buffer. Because the used_clrs parameter dictates how many color entries are processed, an inflated or malformed value causes the iteration logic to traverse beyond the end of the intended array. This results in reading arbitrary bytes from adjacent heap memory structures rather than stopping at the correct boundary. The immediate operational consequence is often an application crash due to segmentation faults or access violations triggered by the operating system's protection mechanisms when invalid memory addresses are accessed.
The impact of this vulnerability extends beyond simple service disruption. While a denial of service resulting from application crashes is the most observable effect, the heap out-of-bounds read also poses a significant risk for information disclosure. By reading adjacent memory contents, an attacker may potentially extract sensitive data stored in nearby allocations, such as pointers to other objects, cryptographic keys, or user credentials if they reside in the same process space. Although GIMP is primarily a desktop application and not typically exposed to remote network attacks, this flaw remains critical for users who open untrusted image files from external sources, including email attachments or downloaded content. The ability to leak heap memory contents can aid further exploitation by revealing internal state information that could be leveraged in more complex attack chains involving code execution vulnerabilities elsewhere in the application stack.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-125, which describes Out-of-bounds Read, and specifically relates to improper input validation as defined under CWE-20. In terms of adversary tactics, this flaw facilitates reconnaissance activities by allowing an attacker to gather information about the target environment through memory leakage, corresponding to ATT&CK technique T1005, Data from Local System. The lack of bounds checking is a classic example of insufficient boundary verification that persists in legacy codebases where manual buffer management is required without modern safety abstractions.
Mitigation strategies for this vulnerability primarily involve updating the GIMP software to versions where the file-ico plugin has been patched with stricter validation logic. Developers must ensure that the used_clrs parameter is validated against the actual size of the palette data present in the ICO file before any memory access occurs. This includes verifying that the count does not exceed the number of available color entries and ensuring that all subsequent array accesses remain within allocated heap boundaries. For end-users, the immediate mitigation involves avoiding opening ICO files from untrusted sources until a patched version is installed. Additionally, employing sandboxing techniques or running GIMP with restricted privileges can limit the potential impact if an exploit attempt occurs, reducing the risk of sensitive data exposure to other processes on the system.