CVE-2021-29363 in IrfanView
Summary
by MITRE • 09/28/2021
A buffer overflow vulnerability in FORMATS!ReadRAS_W+0xa74 of Irfanview 4.57 allows attackers to execute arbitrary code via a crafted RLE file.0xa74
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 05/06/2026
The buffer overflow vulnerability identified as CVE-2021-29363 resides within the IrfanView image viewer version 4.57 at the specific memory offset 0xa74 in the FORMATS!ReadRAS_W function. This flaw represents a classic stack-based buffer overflow condition that occurs when processing RLE (Run-Length Encoded) image files, making it particularly dangerous for attackers seeking to exploit image parsing functionality. The vulnerability manifests when the application attempts to read and process malformed RLE data without proper bounds checking, creating an opportunity for memory corruption that can be leveraged for code execution.
This vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a critical weakness in software security architecture. The flaw demonstrates a failure in input validation and memory management practices within the image processing pipeline of IrfanView. Attackers can craft malicious RLE files that trigger the buffer overflow condition, causing the program to write beyond allocated memory boundaries and potentially overwrite critical program execution elements such as return addresses or function pointers. The specific offset 0xa74 indicates the precise location within the ReadRAS_W function where the memory corruption occurs, suggesting a well-defined exploitation vector that security researchers and attackers can target with precision.
The operational impact of this vulnerability extends beyond simple code execution, as it can be leveraged to achieve arbitrary code execution within the context of the IrfanView process. This represents a severe privilege escalation risk since many users may unknowingly open malicious image files, particularly in email attachments or file sharing scenarios. The vulnerability's exploitation capability aligns with ATT&CK technique T1068, which covers 'Local Privilege Escalation' through the exploitation of software vulnerabilities. The attack surface is particularly concerning given IrfanView's widespread use in both personal and enterprise environments, where it serves as a default image viewer for numerous file types including the vulnerable RLE format.
Mitigation strategies should focus on immediate patch application from IrfanView's official distribution channels, as the vendor has likely released a fixed version addressing this memory corruption issue. Security administrators should implement network-based detection measures to identify and block suspicious RLE file transfers, particularly in enterprise environments where users may encounter untrusted image files. Additionally, user education regarding safe file handling practices and the importance of keeping software updated remains critical. The vulnerability demonstrates the importance of input validation and memory safety practices, particularly in image processing libraries where format parsing can introduce complex attack vectors. Organizations should also consider implementing application whitelisting controls and sandboxing techniques to limit the potential impact of successful exploitation attempts, as the buffer overflow could be combined with other techniques to achieve more sophisticated attack objectives.