CVE-2026-40919: GIMP Buffer Overflow Vulnerability

CVE-2026-40919 Overview

A buffer overflow vulnerability has been identified in GIMP's file-seattle-filmworks plugin. This security flaw can be exploited when a user opens a specially crafted Seattle Filmworks file, potentially allowing a remote attacker to cause a denial of service (DoS) condition. The vulnerability leads to plugin crashes and may impact the overall stability of the GIMP application.

Critical Impact

Opening malicious Seattle Filmworks files can crash GIMP's file-seattle-filmworks plugin, causing denial of service and application instability.

Affected Products

• GIMP (GNU Image Manipulation Program)
• GIMP file-seattle-filmworks plugin

Discovery Timeline

• 2026-04-15 - CVE CVE-2026-40919 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2026-40919

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write), which occurs when the application writes data past the end or before the beginning of the intended buffer. In the context of GIMP's file-seattle-filmworks plugin, the flaw manifests during the parsing of Seattle Filmworks image files. When processing a maliciously crafted file, the plugin fails to properly validate input boundaries, resulting in a buffer overflow condition.

The attack requires local access and user interaction, as the victim must open a specially crafted file. While the vulnerability does not result in confidentiality impact, it can cause high availability impact through application crashes and limited integrity impact through memory corruption.

Root Cause

The root cause lies in insufficient boundary checking within the file-seattle-filmworks plugin when processing Seattle Filmworks file format data. The plugin allocates a fixed-size buffer for file parsing operations but does not adequately validate that incoming data fits within the allocated memory space. When a crafted file contains oversized or malformed data structures, the plugin writes beyond the buffer boundaries, corrupting adjacent memory regions.

Attack Vector

The attack vector requires local access with user interaction. An attacker would craft a malicious Seattle Filmworks file designed to trigger the buffer overflow condition. The attack scenario typically involves:

1. The attacker creates a specially crafted Seattle Filmworks file containing malformed data that exceeds expected buffer sizes
2. The victim downloads or receives the malicious file through email, web download, or file sharing
3. The victim opens the file using GIMP, which invokes the vulnerable file-seattle-filmworks plugin
4. The plugin attempts to parse the malformed data, triggering the buffer overflow
5. The overflow corrupts memory, causing the plugin to crash and potentially destabilizing GIMP

The vulnerability mechanism involves improper bounds checking during file parsing operations. When the plugin reads data from a Seattle Filmworks file, it copies input data into a stack or heap buffer without verifying the data length. A malicious file with oversized data fields causes the write operation to exceed buffer boundaries. For technical details, see the Red Hat CVE-2026-40919 Advisory and Red Hat Bug 2458748 Report.

Detection Methods for CVE-2026-40919

Indicators of Compromise

• Unexpected crashes of the GIMP application when opening Seattle Filmworks files
• GIMP plugin crash logs indicating memory access violations in the file-seattle-filmworks plugin
• System logs showing segmentation faults or memory corruption errors associated with GIMP processes
• Presence of suspicious or unexpected Seattle Filmworks format files (.pws or similar extensions) in user download directories

Detection Strategies

• Monitor system logs for GIMP process crashes accompanied by memory violation error codes
• Implement file inspection rules to detect malformed Seattle Filmworks files with anomalous data structures
• Deploy endpoint detection rules to alert on repeated GIMP crashes following file open operations
• Use application crash monitoring to identify patterns consistent with exploit attempts

Monitoring Recommendations

• Enable crash reporting for GIMP to capture detailed information about plugin failures
• Implement file quarantine policies for Seattle Filmworks format files from untrusted sources
• Monitor for unusual file download patterns involving legacy image formats
• Configure SentinelOne to track GIMP process behavior and detect abnormal terminations

How to Mitigate CVE-2026-40919

Immediate Actions Required

• Avoid opening Seattle Filmworks files from untrusted or unknown sources until patched versions are available
• Consider temporarily disabling or removing the file-seattle-filmworks plugin if not required for workflow
• Apply vendor security patches as they become available from GIMP development team
• Ensure all GIMP installations are updated to the latest available version

Patch Information

Monitor the following resources for patch availability and security updates:

• Red Hat CVE-2026-40919 Advisory - Official Red Hat security advisory
• Red Hat Bug 2458748 Report - Bug tracking and patch status

Organizations using GIMP should subscribe to security announcement channels and apply patches promptly when released by upstream GIMP developers or distribution maintainers.

Workarounds

• Disable or uninstall the file-seattle-filmworks plugin from GIMP if Seattle Filmworks file support is not required
• Implement file filtering at email gateways and web proxies to block Seattle Filmworks format files
• Use application sandboxing to isolate GIMP and limit the impact of potential crashes
• Convert Seattle Filmworks files using alternative tools before opening in GIMP

# Disable file-seattle-filmworks plugin by removing or renaming
# Navigate to GIMP plugin directory and disable the vulnerable plugin
cd ~/.config/GIMP/2.10/plug-ins/
# Rename or move the plugin to disable it
mv file-seattle-filmworks file-seattle-filmworks.disabled

# For system-wide installations, adjust permissions (requires root)
# sudo chmod 000 /usr/lib/gimp/2.0/plug-ins/file-seattle-filmworks