CVE-2021-29365 in Irfanview 4.57
Summary
by MITRE • 09/28/2021
Irfanview 4.57 is affected by an infinite loop when processing a crafted BMP file in the EFFECTS!AutoCrop_W component. This can cause a denial of service (DOS).
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Analysis
by VulDB Data Team • 05/06/2026
The vulnerability identified as CVE-2021-29365 affects IrfanView version 4.57 and represents a denial of service condition arising from improper input validation within the EFFECTS!AutoCrop_W component. This flaw manifests when the software processes a specially crafted bmp file that triggers an infinite loop during the image processing workflow. The vulnerability stems from inadequate boundary checking and loop termination conditions within the bitmap image handling routines, specifically within the AutoCrop functionality that is part of the Effects plugin architecture.
The technical implementation of this vulnerability involves the manipulation of specific bmp file headers or pixel data structures that cause the AutoCrop_W component to enter a processing loop that never terminates. When the vulnerable IrfanView application attempts to process the malicious bmp file, the control flow becomes trapped in a repetitive cycle where the application continuously executes the same set of operations without advancing toward completion. This behavior directly violates the expected execution flow and consumes excessive system resources including cpu cycles and memory allocation. The flaw is classified as a weakness in the software's input validation mechanisms, aligning with CWE-835 which addresses infinite loops or iterations that do not terminate properly.
From an operational perspective, this vulnerability presents a significant risk to systems that rely on IrfanView for image processing tasks, particularly in environments where automated image handling or batch processing occurs. The denial of service condition effectively renders the application unresponsive or completely non-functional until manually terminated by an administrator. Attackers could exploit this vulnerability by distributing malicious bmp files through various attack vectors including email attachments, web downloads, or file sharing platforms. The impact extends beyond simple application disruption as it can affect workflow automation processes, automated image analysis systems, and any application that integrates with IrfanView for image processing capabilities. This vulnerability is particularly concerning in enterprise environments where IrfanView may be used as part of larger document management or digital asset processing systems.
The mitigation strategies for this vulnerability should focus on immediate software updates and patches provided by the vendor, which typically involve fixing the loop termination conditions within the AutoCrop_W component. Organizations should implement network segmentation and file validation controls to prevent the execution of untrusted image files, particularly those that may be automatically processed by vulnerable applications. Security controls should include monitoring for unusual cpu utilization patterns that may indicate denial of service conditions, as well as implementing file type restrictions and content validation for image files in critical processing workflows. The vulnerability also highlights the importance of proper input validation and boundary checking in image processing libraries, which aligns with ATT&CK technique T1203 for legitimate program execution and T1499 for disruption of services. Additionally, organizations should consider implementing application whitelisting policies to restrict execution of vulnerable software versions until proper patches are deployed across all affected systems.