Bug 2520299 (CVE-2026-77118)

Summary: CVE-2026-77118 GraphicsMagick: GraphicsMagick: Arbitrary code execution via crafted PCD file
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in GraphicsMagick. A heap out-of-bounds write vulnerability exists in the Photo CD (PCD) decoder. A remote attacker could exploit this by providing a specially crafted PCD file. Processing this file can lead to corruption of heap memory, potentially resulting in arbitrary code execution.
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Bug Depends On: 2521292, 2521293    
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Description OSIDB Bzimport 2026-08-20 13:11:33 UTC 
A heap out-of-bounds write exists in the Photo CD (PCD) decoder of GraphicsMagick. In DecodeImage() (coders/pcd.c), the Huffman delta loop advances its output pointer with q++ after every decoded delta and never checks it against the end of the heap-allocated luma/chroma plane buffers. The pointer is repositioned only when a sync marker introduces a new plane/row; between sync markers the run length is bounded solely by the input.



A crafted PCD file that positions the pointer near the end of a plane and then supplies a long run of deltas with no intervening sync therefore walks the pointer past the end of the allocation and writes through it. Processing an untrusted PCD file — for example with gm convert or gm identify, or through any application linked against libGraphicsMagick — can corrupt heap memory beyond the buffers.