CVE-2026-82343 in Red Hat
Summary
by MITRE • 08/28/2026
A flaw was found in the file-psd plugin in GIMP. When processing a specially crafted PSD image file, the plugin does not properly validate the channel-count parameter. This incorrect validation leads to improper memory bounds checking, resulting in both a heap out-of-bounds read and a stack out-of-bounds access. This issue can result in an application crash, leading to a denial of service or a limited information disclosure of memory contents.
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Analysis
by VulDB Data Team • 08/28/2026
The vulnerability identified within the file-psd plugin for GIMP represents a critical failure in input validation mechanisms when processing Photoshop Document files. The core technical flaw stems from the improper handling of the channel-count parameter embedded within the PSD file structure. When the application parses this metadata, it fails to rigorously verify that the specified number of channels aligns with the actual data present or expected by the internal memory allocation routines. This lack of strict boundary checking allows a maliciously crafted PSD image to manipulate how much memory is accessed during the rendering and processing phases. The consequence of this logic error manifests in two distinct memory corruption vectors: a heap out-of-bounds read and a stack out-of-bounds access. These conditions arise because the application proceeds to allocate or reference memory regions based on untrusted input values without ensuring those regions exist within valid limits, leading to reads from unauthorized memory addresses both on the dynamic heap and the execution stack.
From an operational perspective, this vulnerability primarily facilitates denial of service attacks against users who open maliciously constructed PSD files. The immediate result is typically a segmentation fault or application crash as the program attempts to access invalid memory locations. However, beyond simple disruption, the presence of out-of-bounds reads introduces significant risks related to information disclosure. By reading from heap and stack regions outside their intended boundaries, an attacker may potentially extract sensitive data stored in adjacent memory blocks. This could include partial contents of other open files, cryptographic keys, session tokens, or internal application state variables that were previously written to those memory locations. While the exploitation complexity is moderate due to the need for precise crafting of the PSD file structure, the impact on confidentiality and availability remains substantial for users relying on GIMP as a primary image editing tool in untrusted environments.
This vulnerability aligns with Common Weakness Enumeration CWE-125, which describes out-of-bounds read vulnerabilities where software reads data past the end or before the beginning of the intended buffer. Additionally, it relates to CWE-787, concerning out-of-bounds write access on the stack, although in this specific instance, the primary risk is information disclosure via reading rather than code execution via writing. In terms of adversary tactics, this flaw supports techniques categorized under ATT&CK T1005, which involves data from local system memory extraction. Attackers can leverage such vulnerabilities to gather intelligence about the victim's environment without triggering immediate alarms associated with more aggressive exploitation methods like remote code execution. The lack of proper validation on a commonly used file format parameter makes this a persistent threat vector for social engineering attacks where users are tricked into opening seemingly legitimate but maliciously crafted image files.
Mitigation strategies must focus on both defensive coding practices and operational security measures. Developers should implement strict input validation that verifies the channel-count against expected bounds before any memory allocation or access operations occur. This includes ensuring that the number of channels does not exceed predefined limits based on the PSD specification and verifying that sufficient data is available in the file to support the requested operation. Runtime protection mechanisms such as Address Space Layout Randomization (ASLR) and stack canaries should be enabled to mitigate the impact of memory corruption, although they do not prevent the initial vulnerability. For end-users, it is advisable to avoid opening PSD files from untrusted sources until patches are applied. Organizations deploying GIMP in shared or public-facing environments should consider sandboxing the application to limit the potential blast radius if a crash occurs and restrict network access for processes handling user-uploaded images to minimize lateral movement opportunities following any successful exploitation attempt.