CVE-2026-2049: GIMP HDR File Parsing RCE Vulnerability

CVE-2026-2049 Overview

CVE-2026-2049 is a heap-based buffer overflow in GIMP that enables arbitrary code execution when a user opens a crafted High Dynamic Range (HDR) image file. The flaw resides in the HDR file parser, which copies user-supplied data into a heap buffer without validating its length. Successful exploitation results in code execution in the context of the current GIMP process. The issue was reported through the Zero Day Initiative as ZDI-CAN-28618 and tracked upstream in the GEGL project on GNOME GitLab.

Critical Impact

Attackers can achieve arbitrary code execution on systems where a user opens a malicious HDR file in GIMP, compromising the integrity and confidentiality of the host process.

Affected Products

• GIMP (GNU Image Manipulation Program)
• GEGL image processing library used by GIMP
• Applications that embed the affected GEGL HDR loader

Discovery Timeline

• 2026-06-10 - CVE-2026-2049 published to the National Vulnerability Database (NVD)
• 2026-06-10 - Last updated in NVD database
• Reported through the Zero Day Initiative as ZDI-CAN-28618 and published as advisory ZDI-26-214

Technical Details for CVE-2026-2049

Vulnerability Analysis

The vulnerability is a heap-based buffer overflow [CWE-122] in the HDR image format parser used by GIMP through the GEGL library. HDR files use the Radiance RGBE format, which encodes high dynamic range pixel data and includes header fields describing image dimensions and run-length encoded scanline data. The parser allocates a heap buffer based on assumed structural constraints, then copies attacker-controlled bytes from the file into that buffer without enforcing length checks.

When the supplied data exceeds the buffer size, adjacent heap memory is overwritten. Attackers can shape allocations and overflow contents to corrupt heap metadata or adjacent objects, ultimately redirecting control flow. The attack requires the victim to open or preview a malicious HDR file, which can be delivered through email, web downloads, file shares, or thumbnail handlers.

Root Cause

The root cause is missing validation of the length of user-supplied data prior to a copy operation into a heap-allocated buffer in the HDR loader. The parser trusts size or count fields derived from the file rather than comparing them against the allocated destination size before copying.

Attack Vector

Exploitation requires local user interaction. The user must open or render a malicious HDR file in GIMP. The attack runs in the security context of the GIMP process, granting the attacker the privileges of the user opening the file. No authentication or network access to the host is required beyond delivering the file to the target.

No verified public proof-of-concept code is available. See the upstream GNOME GEGL Issue #450 and the Zero Day Initiative Advisory ZDI-26-214 for technical details.

Detection Methods for CVE-2026-2049

Indicators of Compromise

• HDR files (.hdr, Radiance RGBE) received from untrusted sources, especially with unusually large dimension fields or malformed headers.
• GIMP process crashes, unexpected child processes spawned from gimp or gimp-console, or memory corruption signatures in system logs.
• Outbound network connections originating from the GIMP process shortly after opening an image file.

Detection Strategies

• Inspect HDR file headers for inconsistent width, height, or scanline length values that exceed plausible bounds.
• Hunt for GIMP processes spawning shells, scripting interpreters, or network utilities (sh, bash, cmd.exe, powershell.exe, curl, wget).
• Correlate file-open telemetry for .hdr extensions with subsequent process or network anomalies on the same host.

Monitoring Recommendations

• Enable process and file telemetry on workstations where GIMP is installed and forward events to a centralized analytics platform.
• Alert on GIMP crashes that produce core dumps or Windows Error Reporting events tied to heap corruption.
• Track delivery of HDR attachments through email and web gateways and submit suspicious samples for sandbox analysis.

How to Mitigate CVE-2026-2049

Immediate Actions Required

• Apply the upstream GIMP and GEGL updates that address the HDR parser flaw as soon as vendor packages become available.
• Restrict opening of HDR files from untrusted sources until patched builds are deployed across endpoints.
• Communicate guidance to users who routinely process image files, emphasizing the user-interaction requirement for exploitation.

Patch Information

Patch tracking is maintained upstream in the GEGL project. Refer to GNOME GEGL Issue #450 for the fix status and to the Zero Day Initiative Advisory ZDI-26-214 for coordinated disclosure information. Update GIMP and GEGL packages through your Linux distribution, Flatpak, Snap, macOS, or Windows installer once fixed versions are released.

Workarounds

• Disable HDR thumbnailing and preview handlers in file managers to prevent automatic parsing of .hdr files.
• Block or quarantine inbound .hdr attachments at email and web proxy gateways until patches are deployed.
• Run GIMP under a least-privilege user account or within a sandbox such as Flatpak with restricted filesystem access.

# Example: block HDR file execution path on Linux by removing thumbnailer entry
sudo rm -f /usr/share/thumbnailers/gegl-hdr.thumbnailer
# Verify installed GIMP and GEGL versions
gimp --version
pkg-config --modversion gegl-0.4