CVE-2026-96546 in GIMP
Summary
by MITRE • 09/23/2026
A one-byte out-of-bounds heap read flaw was found in GIMP's uncompressed DDS image loader. When a user opens an uncompressed DDS image, the file-dds plug-in performs an unconditional one-byte look-ahead after processing the final pixel. This may cause the plug-in to crash if the byte immediately following the pixel buffer is inaccessible; no information disclosure or code execution has been demonstrated.
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Analysis
by VulDB Data Team • 09/23/2026
The vulnerability identified in GIMP involves a critical memory access error within its uncompressed DDS image loading module, specifically classified as an out-of-bounds heap read. This flaw stems from improper boundary checking during the parsing of Digital Visual Interface (DVI) Data Stream Standard files that utilize uncompressed pixel data formats. The core technical issue lies in the file-dds plug-in's logic for processing pixel buffers. After iterating through and rendering all valid pixels defined by the image dimensions, the software executes an unconditional read operation to access a single byte located immediately after the end of the allocated heap buffer containing the pixel data. This behavior is typically intended as a look-ahead mechanism to detect specific file markers or termination conditions in stream-based parsers, but it fails to validate whether this subsequent memory location falls within the bounds of the currently mapped allocation.
From a technical perspective, this constitutes an Out-of-Bounds Read vulnerability, aligning with Common Weakness Enumeration identifier CWE-125. The heap buffer containing the uncompressed pixel data is allocated based on the width and height specified in the DDS header. However, the parser does not account for the fact that reading one byte beyond the end of this allocation may access memory that has already been freed or belongs to a different object managed by the allocator. In many modern operating systems with heap protection mechanisms such as Address Space Layout Randomization (ASLR) and stack canaries, accessing unmapped pages triggers an immediate segmentation fault. This results in a denial-of-service condition where the GIMP application crashes unexpectedly when attempting to open a crafted or malformed DDS file that exploits this boundary miscalculation.
The operational impact of this vulnerability is primarily limited to service availability rather than confidentiality or integrity. As noted, no information disclosure has been demonstrated because the single byte read does not provide sufficient data for meaningful exfiltration without further exploitation techniques like heap spraying or specific memory layout knowledge. Similarly, code execution is not directly achievable through this flaw alone since it involves a read operation rather than a write operation that could overwrite function pointers or return addresses. However, in complex software environments, such out-of-bounds reads can sometimes lead to undefined behavior depending on the surrounding memory state, potentially creating opportunities for more sophisticated attacks if combined with other vulnerabilities. For end-users and system administrators, this represents a risk of application instability when handling untrusted image files obtained from external sources or malicious websites hosting deceptive media content.
Mitigation strategies should focus on both immediate patching and long-term defensive coding practices. The primary remediation is the deployment of vendor-provided updates that correct the boundary check logic within the file-dds plug-in to ensure no memory access occurs beyond the allocated buffer size. In environments where GIMP cannot be immediately updated, users should exercise caution when opening DDS files from untrusted origins and consider using alternative image viewers with stricter input validation for their initial triage of suspicious media. Furthermore, this incident highlights the importance of adopting secure coding standards that mandate explicit bounds checking before any memory access operation. Integrating static analysis tools into the development pipeline can help detect such off-by-one errors early in the software lifecycle, reducing the attack surface associated with image processing libraries and preventing similar vulnerabilities from being introduced in future releases.