Description

A flaw was found in the file-pvr plugin in GIMP. When processing a specially crafted PVR image file, the VQ (compressed) decoder does not properly perform memory bounds checking. This missing validation results 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.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.1",
  "pubDate": "2026-08-28T16:18:34.347Z",
  "pubdate": "2026-08-28T16:18:34.347Z",
  "executiveSummary": "A heap-based out-of-bounds read vulnerability exists within the file-pvr plugin of GIMP, specifically during the processing of compressed PVR (PowerVR) image files.\nThe vulnerability stems from improper memory bounds validation within the VQ (Vector Quantization) decoder, allowing an attacker to trigger an out-of-bounds memory access.\nSuccessful exploitation of this flaw can lead to application termination resulting in a denial-of-service (DoS) condition, or potentially facilitate the disclosure of sensitive heap memory contents.\nThis vulnerability requires an attacker to provide a specially crafted PVR file to a victim using an affected version of GIMP. The impact is primarily localized to the application's process memory, although information leakage could assist in bypasses of other security controls like ASLR.\nThe flaw affects the processing logic of the PVR image parser, necessitating no specific authentication or elevated privileges, provided the attacker can induce the user to open the malicious file.",
  "technicalDetails": "The vulnerability resides in the VQ (Vector Quantization) decoding routine of the file-pvr plugin in GIMP. The PVR format utilizes various compression techniques, and the decoder is responsible for translating compressed data blocks into a pixel representation. The root cause of this vulnerability is a lack of rigorous bounds checking when the decoder reads from memory buffers associated with the VQ decoding process.\nWhen a specially crafted PVR file is parsed, the VQ decoder attempts to access heap-allocated memory based on indices or offsets contained within the image data. Because the plugin fails to validate these indices against the actual allocated size of the destination or source buffers, it performs an out-of-bounds read. By manipulating the values within the file headers or compressed data blocks, an attacker can influence the offset used by the decoder to read memory outside the intended buffer boundaries.\nThe attack flow begins when a user is convinced to open a malicious PVR file via the GIMP interface. As the file-pvr plugin parses the file structure, the vulnerable VQ decoder is invoked. During the execution of the decoding loop, the engine consumes attacker-supplied metadata that specifies memory access operations. If the metadata forces an out-of-bounds pointer calculation, the application accesses arbitrary heap memory that follows or precedes the legitimate buffer. This access can result in a segmentation fault if the read operation hits unmapped memory, causing a crash and DoS.\nAlternatively, if the out-of-bounds read is handled by the application logic, the content of the adjacent heap memory may be copied into the rendered image data. This provides a mechanism for information disclosure, as the leaked memory content is essentially serialized and written into the GIMP image buffer, which can then be inspected by the attacker. This can be particularly dangerous if the heap memory contains pointers, cryptographic keys, or other sensitive user data from prior operations. The vulnerability does not require prior authentication or elevated privileges, as it is a client-side parsing flaw that triggers upon the standard file processing operations inherent to the application."
}