CVE-2026-92183: GIMP APNG Parser RCE Vulnerability

CVE-2026-92183 Overview

CVE-2026-92183 is a stack-based buffer overflow [CWE-121] in the GNU Image Manipulation Program (GIMP) that enables arbitrary code execution. The flaw resides in the parser that handles Animated Portable Network Graphics (APNG) files. GIMP fails to validate the length of user-supplied data before copying it to a fixed-size stack buffer. An attacker who convinces a user to open a crafted APNG file, or to visit a page that delivers one, can execute code in the context of the GIMP process. The issue was reported through the Trend Micro Zero Day Initiative under identifier ZDI-CAN-29400 and tracked publicly as ZDI-26-713.

Critical Impact

Successful exploitation allows arbitrary code execution with the privileges of the user running GIMP, enabling full compromise of the user's session, files, and credentials stored on the host.

Affected Products

• GNOME GIMP (versions prior to the commit 175e28961a4679be8762a2d4d5a297faa82aebd9)
• GIMP installations that process APNG files via the file-png plug-in
• Downstream Linux distribution packages that ship vulnerable GIMP builds

Discovery Timeline

• 2026-10-21 - CVE-2026-92183 published to the National Vulnerability Database
• 2026-10-22 - Last updated in NVD database

Technical Details for CVE-2026-92183

Vulnerability Analysis

The vulnerability sits in GIMP's APNG file parsing path. APNG extends the PNG format with chunks such as acTL, fcTL, and fdAT to describe animation frames. When GIMP ingests these chunks, it reads length fields and payload data from the file and copies them into a stack-allocated buffer without verifying that the source data fits the destination. An attacker who controls the chunk length can write beyond the buffer boundary and corrupt adjacent stack memory, including saved return addresses and function pointers.

Exploitation requires user interaction. The target must open a malicious APNG in GIMP or trigger a workflow that passes an attacker-controlled file to the parser, such as a thumbnailer or image preview integration. Because the attack runs in the context of the current process, the attacker gains the same file system, network, and credential access as the user.

Root Cause

The root cause is missing bounds validation prior to a stack buffer copy, classified as [CWE-121] Stack-based Buffer Overflow. The parser trusts length values embedded in untrusted file data. The upstream fix is published in GNOME GIMP commit 175e28961a4679be8762a2d4d5a297faa82aebd9, which adds the required length checks before data is written to the stack buffer.

Attack Vector

The attack vector is local but requires user interaction. Delivery paths include email attachments, drive-by downloads of image files, shared network drives, and chat or collaboration platforms that render user-supplied media. On systems where GIMP is registered as the default handler for .png or .apng files, a double-click is sufficient to invoke the vulnerable parser.

No verified public exploit code is available at the time of publication. See the Zero Day Initiative Advisory ZDI-26-713 and the GNOME GIMP Commit Update for the authoritative technical description.

Detection Methods for CVE-2026-92183

Indicators of Compromise

• APNG or PNG files with malformed acTL, fcTL, or fdAT chunk length fields that exceed documented bounds.
• Unexpected child processes spawned by the gimp binary, such as shells, scripting interpreters, or network utilities.
• Crash dumps or core files generated by GIMP referencing stack corruption during image load operations.

Detection Strategies

• Monitor process creation events where the parent is gimp-2.10, gimp-3.0, or related plug-in executables and the child is an interactive shell or curl, wget, or python.
• Inspect endpoint telemetry for GIMP processes making outbound network connections immediately after opening an image file.
• Deploy YARA rules that flag PNG files containing oversized or malformed APNG animation chunks.

Monitoring Recommendations

• Log and alert on GIMP crashes recorded by systemd-coredump, Windows Error Reporting, or macOS CrashReporter.
• Track file-open events for .apng and .png extensions originating from untrusted locations such as browser download directories or email attachment caches.
• Correlate image file opens with subsequent anomalous user-session behavior, including credential access or lateral movement attempts.

How to Mitigate CVE-2026-92183

Immediate Actions Required

• Update GIMP to a build that includes commit 175e28961a4679be8762a2d4d5a297faa82aebd9 as soon as the fixed release reaches your distribution channel.
• Instruct users to avoid opening APNG or PNG files from untrusted sources until the patch is deployed.
• Audit systems for third-party plug-ins or thumbnailers that invoke GIMP's PNG parser automatically and disable them where feasible.

Patch Information

The upstream fix is available in the GNOME GIMP repository at commit 175e28961a4679be8762a2d4d5a297faa82aebd9. Review the GNOME GIMP Commit Update for the exact code changes, and track vendor advisories from your Linux distribution, Flatpak, Snap, Windows installer, or macOS package maintainer for the corresponding versioned release.

Workarounds

• Remove GIMP's association with .apng and .png file extensions until a patched version is installed.
• Run GIMP inside a sandbox such as Flatpak with restricted file system and network permissions to limit the impact of successful exploitation.
• Disable automatic image previews and thumbnailing in file managers that invoke GIMP as a backend parser.

# Verify the installed GIMP version and remove unpatched builds on Debian/Ubuntu
dpkg -l | grep -i gimp
sudo apt-get update && sudo apt-get install --only-upgrade gimp

# On RHEL/Fedora systems
rpm -q gimp
sudo dnf upgrade gimp

# Flatpak-based deployments
flatpak update org.gimp.GIMP