CVE-2021-29364 in IrfanView
Summary
by MITRE • 09/28/2021
A buffer overflow vulnerability in Formats!ReadRAS_W+0x1001 of Irfanview 4.57 allows attackers to execute arbitrary code via a crafted RLE file.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 05/06/2026
The buffer overflow vulnerability identified as CVE-2021-29364 resides within the IrfanView image processing software version 4.57 specifically within the Formats!ReadRAS_W+0x1001 function. This flaw represents a critical security weakness that enables remote code execution through maliciously crafted RLE (Run-Length Encoded) image files. The vulnerability manifests when the application attempts to process specially constructed RLE data that exceeds the allocated buffer space, creating conditions where adjacent memory regions can be overwritten with attacker-controlled data. This particular implementation flaw affects the RAS (Raster) image format handling module, which is part of IrfanView's extensive format support capabilities that enable the software to read and display numerous image file types.
The technical exploitation of this vulnerability follows a classic buffer overflow attack pattern where insufficient input validation allows an attacker to write beyond the bounds of a predetermined memory buffer. The vulnerability is categorized under CWE-121 as a stack-based buffer overflow, where the attacker can manipulate the program flow by overwriting return addresses, function pointers, or other critical control data structures. When processing the malicious RLE file, the application fails to properly validate the length of data being read, allowing the attacker to inject malicious code into the program's memory space. The offset +0x1001 in the function name suggests this occurs during the processing phase of RAS format reading, where the software allocates a fixed-size buffer without adequate bounds checking for variable-length RLE data sequences.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with a potential foothold for more sophisticated attacks within systems running vulnerable versions of IrfanView. Attackers can leverage this weakness through social engineering tactics by distributing malicious RLE files through email attachments, compromised websites, or file-sharing platforms where users might unknowingly open the crafted images. The vulnerability affects both local and remote execution scenarios since any system that processes these image files through IrfanView could be compromised, making it particularly dangerous in enterprise environments where image processing is common. This vulnerability aligns with ATT&CK technique T1059.007 for command and script interpreter execution, as successful exploitation would allow attackers to execute arbitrary commands on the target system.
Mitigation strategies for CVE-2021-29364 primarily focus on immediate software updates and operational security measures. Users should immediately upgrade to IrfanView version 4.58 or later, which contains patches addressing this specific buffer overflow vulnerability. Organizations should implement strict file validation procedures for image files received from external sources and consider deploying sandboxing solutions when processing untrusted image content. Network administrators should monitor for suspicious file downloads and implement email filtering rules that block potentially malicious image files. Security teams should also consider disabling unnecessary image format support in IrfanView if the software is used in high-security environments, reducing the attack surface. Additionally, regular security assessments should include verification of software versions and patch status to ensure all systems remain protected against known vulnerabilities, particularly those that allow for remote code execution and privilege escalation.