CVE-2021-29360 in IrfanView
Summary
by MITRE • 09/28/2021
A buffer overflow vulnerability in FORMATS!Read_Utah_RLE+0x37a 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-2021-29360 represents a critical buffer overflow flaw within IrfanView version 4.57 that specifically affects the FORMATS!Read_Utah_RLE function at offset 0x37a. This issue arises from inadequate input validation when processing Utah RLE image files, creating a scenario where maliciously crafted data can overwrite adjacent memory regions. The vulnerability falls under the CWE-121 buffer overflow category, which is classified as a critical weakness in memory safety that allows attackers to manipulate program execution flow by overwriting memory locations. The affected component processes RLE (Run-Length Encoding) formatted image files, a common format used for compressing raster graphics data, making this vulnerability particularly dangerous as it can be exploited through standard image file handling operations.
The technical exploitation of this vulnerability occurs when IrfanView attempts to parse a malformed RLE file that contains excessive data beyond the allocated buffer space. The buffer overflow at offset 0x37a in the Read_Utah_RLE function allows attackers to overwrite return addresses, function pointers, or other critical memory structures within the application's execution context. This memory corruption directly enables arbitrary code execution, as demonstrated by the ability to inject and execute malicious payloads through the vulnerable parsing routine. The vulnerability is particularly concerning because it requires no special privileges to exploit, as it operates within the context of the application itself, making it a prime target for social engineering attacks through malicious image files delivered via email attachments, web downloads, or other file transfer mechanisms.
From an operational perspective, this vulnerability presents significant risk to end users and organizations that rely on IrfanView for image processing tasks. The exploitability of the flaw means that simply opening a maliciously crafted RLE file can result in complete system compromise, as the application's memory layout allows for direct code execution without requiring additional attack vectors. The vulnerability affects the application's image parsing functionality, which is commonly used for viewing images in various contexts including office environments, web browsing, and digital media processing workflows. Security analysts should note that this vulnerability aligns with ATT&CK technique T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter), as it enables attackers to execute arbitrary code through legitimate application interfaces. The attack surface is broad since RLE files are commonly encountered in various digital environments and the vulnerability can be triggered through automated file processing, making it particularly dangerous for unpatched systems.
Mitigation strategies for CVE-2021-29360 should prioritize immediate patching of IrfanView to version 4.58 or later, which contains the necessary memory boundary checks and input validation fixes. Organizations should implement restrictive file handling policies that prevent automatic execution of image files from untrusted sources and consider deploying application whitelisting solutions to prevent execution of vulnerable versions. Network-based defenses should include monitoring for suspicious file types and implementing sandboxing techniques for image file processing. The vulnerability also underscores the importance of regular software updates and vulnerability management programs, as it demonstrates how seemingly benign file format parsing operations can become attack vectors when proper memory safety controls are absent. Security teams should also consider implementing user education programs to prevent accidental execution of malicious files, particularly in environments where users may encounter image files from unknown sources. Additionally, organizations should conduct vulnerability assessments to identify other potentially vulnerable applications within their environment that may share similar parsing routines and buffer handling patterns.