CVE-2026-0797: GIMP ICO File Parsing RCE Vulnerability

CVE-2026-0797 Overview

CVE-2026-0797 is a heap-based buffer overflow vulnerability in GIMP's ICO file parsing functionality that enables remote code execution. The flaw exists due to improper validation of user-supplied data length before copying it to a heap-based buffer when processing ICO image files. Successful exploitation requires user interaction—the target must open a malicious ICO file or visit a malicious webpage containing the crafted image.

This vulnerability was originally tracked as ZDI-CAN-28599 by the Zero Day Initiative before receiving its CVE designation.

Critical Impact

Remote attackers can execute arbitrary code in the context of the current process by tricking users into opening malicious ICO files, potentially leading to complete system compromise.

Affected Products

• GIMP 3.2.0-rc1
• GIMP (additional versions may be affected)

Discovery Timeline

• 2026-02-20 - CVE-2026-0797 published to NVD
• 2026-02-24 - Last updated in NVD database

Technical Details for CVE-2026-0797

Vulnerability Analysis

The vulnerability resides within GIMP's ICO file parsing component and is classified under CWE-122 (Heap-based Buffer Overflow) and CWE-787 (Out-of-bounds Write). When GIMP processes a specially crafted ICO file, insufficient validation of the data length allows an attacker to overflow a heap-based buffer.

Heap-based buffer overflows occur when data is written beyond the allocated boundary of a heap memory region. In this case, the ICO parser fails to properly validate the length of user-supplied data before copying it into a fixed-size heap buffer. This memory corruption primitive can be leveraged to overwrite adjacent heap metadata or application data structures.

Root Cause

The root cause stems from missing or improper bounds checking in the ICO file parsing logic. When processing ICO image data, the application allocates a heap buffer based on expected input size but does not adequately verify that the actual incoming data conforms to these expectations. Malformed ICO files can specify larger data segments than the allocated buffer can accommodate, resulting in heap memory corruption.

Attack Vector

The attack requires local access in the sense that user interaction is mandatory—the victim must be convinced to open a malicious ICO file or navigate to a webpage hosting the malicious content. Attack scenarios include:

1. Email-based attacks: Sending crafted ICO files as email attachments disguised as legitimate images
2. Web-based attacks: Hosting malicious ICO files on compromised or attacker-controlled websites
3. Social engineering: Distributing malicious ICO files through file-sharing platforms or social media

Once the victim opens the malicious ICO file with GIMP, the buffer overflow triggers, allowing the attacker to execute arbitrary code with the same privileges as the GIMP process. This could lead to data theft, malware installation, or further lateral movement within the network.

The vulnerability's exploitation does not require the attacker to have any prior access or privileges on the target system, though user interaction is required to trigger the flaw.

Detection Methods for CVE-2026-0797

Indicators of Compromise

• Anomalous ICO files with malformed headers or unusually large data segments
• GIMP process crashes or unexpected termination when opening ICO files
• Memory access violations or segmentation faults in GIMP logs
• Suspicious child processes spawned by GIMP during or after ICO file processing

Detection Strategies

• Monitor for GIMP process anomalies including unexpected child process creation or network connections
• Implement file integrity monitoring on systems where GIMP processes untrusted ICO files
• Deploy endpoint detection rules to identify heap corruption patterns associated with exploitation attempts
• Analyze ICO files at ingress points for malformed structures before they reach end-user systems

Monitoring Recommendations

• Enable detailed logging for GIMP operations, particularly file open events
• Configure endpoint protection to alert on memory corruption indicators in graphics applications
• Implement network-level inspection for ICO files transferred via email or web downloads
• Review system and application logs for GIMP crash reports that may indicate exploitation attempts

How to Mitigate CVE-2026-0797

Immediate Actions Required

• Update GIMP to the latest patched version that addresses CVE-2026-0797
• Restrict opening ICO files from untrusted sources until patching is complete
• Enable application whitelisting to prevent unauthorized code execution
• Educate users about the risks of opening unsolicited image files

Patch Information

GNOME has released a commit that addresses this vulnerability. The fix is available in the GNOME GIMP repository commit 69cc6b1a6645dc9c4d7b484483dbe6a84b922b9c. Users should update to a GIMP version that includes this security patch. Additional technical details are available in the Zero Day Initiative Advisory ZDI-26-050.

Workarounds

• Disable or remove ICO file type associations with GIMP until patches are applied
• Use alternative image viewers for ICO files that are not affected by this vulnerability
• Implement network-level filtering to block or quarantine ICO files from untrusted sources
• Run GIMP in a sandboxed environment to contain potential exploitation

# Configuration example: Disable ICO file association on Linux
# Remove GIMP as the default handler for ICO files
xdg-mime default "" image/vnd.microsoft.icon
# Alternatively, configure AppArmor profile to restrict GIMP
sudo aa-enforce /etc/apparmor.d/usr.bin.gimp