CVE-2021-29366 in Irfanview 4.57
Summary
by MITRE • 09/28/2021
A buffer overflow vulnerability in FORMATS!GetPlugInInfo+0x2de9 of Irfanview 4.57 allows attackers to execute arbitrary code via a crafted RLE file.
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Analysis
by VulDB Data Team • 05/06/2026
The vulnerability identified as CVE-2021-29366 represents a critical buffer overflow flaw within IrfanView version 4.57 that specifically affects the FORMATS!GetPlugInInfo function at offset 0x2de9. This issue manifests when the application processes specially crafted RLE (Run-Length Encoded) image files, creating a scenario where attacker-controlled data can overwrite adjacent memory locations beyond the allocated buffer boundaries. The vulnerability stems from inadequate input validation and bounds checking within the image parsing routine that handles RLE format decoding, allowing malicious actors to manipulate memory layout and potentially execute arbitrary code with the privileges of the affected application.
The technical implementation of this buffer overflow leverages the inherent weakness in how IrfanView processes RLE image data structures, particularly when parsing plugin information metadata. When the application encounters a malformed RLE file, the GetPlugInInfo function fails to properly validate the size of incoming data before copying it into fixed-size buffers, creating a classic stack-based buffer overflow condition. This flaw operates under CWE-121, which categorizes stack-based buffer overflow vulnerabilities, and aligns with ATT&CK technique T1059.007 for execution through command and scripting interpreter. The vulnerability's exploitation potential is significant as it allows attackers to overwrite return addresses, function pointers, or other critical memory structures, enabling code execution in the context of the running IrfanView process.
The operational impact of CVE-2021-29366 extends beyond simple arbitrary code execution, as it can potentially lead to complete system compromise when IrfanView is used with elevated privileges or in environments where users might unknowingly open malicious files. Attackers can leverage this vulnerability through social engineering campaigns targeting users who frequently handle image files, particularly in corporate or research environments where image processing applications are commonly used. The vulnerability affects not only individual users but also organizations that deploy IrfanView across multiple systems, as a single compromised file can propagate the attack vector throughout the network. Additionally, the exploitability is enhanced by the fact that RLE files are commonly used in various contexts, making them more likely to be encountered in normal user workflows.
Mitigation strategies for CVE-2021-29366 should prioritize immediate application updates to IrfanView version 4.58 or later, which contains the necessary patches to address the buffer overflow condition. System administrators should implement strict file validation policies and deploy application whitelisting solutions to prevent execution of untrusted image files. Network-level protections including intrusion detection systems and web application firewalls can help identify and block malicious RLE file deliveries. Users should be educated about the risks of opening image files from untrusted sources and encouraged to maintain updated software versions. Security monitoring should focus on detecting anomalous file processing activities and potential exploitation attempts, with particular attention to memory corruption patterns that may indicate buffer overflow exploitation. Organizations should also consider implementing sandboxing techniques for image processing applications to limit the potential impact of successful exploitation attempts.