CVE-2026-58380 in GIMP
Summary
by MITRE • 07/06/2026
A flaw was found in GIMP's PNM file format parser. When parsing a specially crafted PNM file, the pnmscanner_gettoken() function writes a null terminator one byte past the end of a stack-allocated buffer due to an off-by-one error in the loop boundary check. This could lead to memory corruption, potentially resulting in denial of service or arbitrary code execution.
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Analysis
by VulDB Data Team • 07/06/2026
The vulnerability identified in GIMP's PNM file format parser represents a critical memory safety issue that exploits an off-by-one error within the pnmscanner_gettoken() function. This flaw specifically manifests when processing maliciously crafted PNM files, where the buffer overflow occurs due to improper loop boundary validation during token parsing operations. The root cause stems from a classic buffer overread condition where memory corruption happens when writing a null terminator one byte beyond the allocated stack buffer boundaries.
This vulnerability operates at the intersection of several cybersecurity domains including software security, memory management, and input validation. The PNM file format parser serves as an entry point for external data processing within GIMP's image handling pipeline, making it a prime target for exploitation attempts. The flaw demonstrates characteristics consistent with CWE-121 Stack-based Buffer Overflow, which occurs when a program writes beyond the bounds of a stack-allocated buffer, potentially overwriting adjacent memory locations including return addresses and function pointers.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass potential arbitrary code execution capabilities. When an attacker successfully crafts a malicious PNM file, the resulting buffer overflow can corrupt critical memory segments that control program execution flow. This memory corruption may manifest as stack smashing, heap corruption, or even overwrite of executable code sections, depending on the specific memory layout during exploitation. The vulnerability's severity is amplified by the fact that it occurs within a widely used image processing application where users frequently open files from untrusted sources.
From an ATT&CK framework perspective, this vulnerability maps to multiple techniques including T1059 Command and Scripting Interpreter and T1203 Exploitation for Client Execution. The attack surface is particularly concerning given that PNM files are commonly encountered in image processing workflows and can be embedded within other file formats or delivered through various attack vectors. Mitigation strategies should include immediate patch deployment for the affected GIMP versions, implementation of strict input validation routines, and runtime protections such as stack canaries or address space layout randomization to reduce exploit reliability.
The technical exploitation requires careful consideration of memory layout constraints and buffer management practices within the affected codebase. Modern exploit mitigation techniques including compiler-based stack protection mechanisms and heap integrity checks should be enabled to prevent successful exploitation attempts. Organizations should prioritize updating their GIMP installations to versions that contain the patched pnmscanner_gettoken() function implementation, while also implementing file format validation procedures that can detect and reject malformed PNM files before they reach the vulnerable parser component.