CVE-2026-86422 in ImageMagick
Summary
by MITRE • 09/07/2026
ImageMagick before 7.1.2-30 contains a time-of-check-time-of-use vulnerability in path policy enforcement on Windows that allows attackers to bypass read or write restrictions by exploiting symlink race conditions. Attackers can swap symlinks between policy validation and file access to read or write policy-denied files.
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Analysis
by VulDB Data Team • 09/07/2026
The identified vulnerability represents a classic time-of-check-time-of-use flaw within the path policy enforcement mechanisms of ImageMagick versions prior to 7.1.2-30, specifically affecting Windows environments. This security defect arises from an inherent race condition where there is a temporal gap between the initial validation of a file path against configured security policies and the subsequent actual access or modification of that file by the application logic. During this interval, if the underlying filesystem state changes due to external manipulation, the policy check becomes invalid for the final operation, allowing attackers to bypass intended read or write restrictions.
The technical mechanism exploits the behavior of symbolic links on Windows operating systems. An attacker can create a malicious symlink pointing to a restricted resource and present it to ImageMagick as an input file. The application performs its security checks at this stage, verifying that the target path is permitted by the current policy configuration. However, if the attacker replaces or redirects the symlink between the moment of validation and the moment of execution, the application will proceed with accessing a different resource than originally checked. This race condition effectively neutralizes the protective measures designed to prevent unauthorized access to sensitive files outside allowed directories.
From an operational perspective, this vulnerability poses significant risks related to confidentiality and integrity. Successful exploitation allows remote or local attackers to read arbitrary files from the system that are normally protected by ImageMagick's policy restrictions, such as configuration files containing credentials or private user data. Furthermore, it enables unauthorized writes to restricted locations, potentially leading to code execution if writable directories like temporary folders or application paths can be targeted for malicious payload injection. The impact is particularly severe in environments where ImageMagick processes untrusted images provided by external users, as this could lead to full system compromise through file-based attack vectors.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-367, which defines time-of-check-time-of-use errors involving race conditions that allow an attacker to bypass security checks. In the context of the MITRE ATT&CK framework, this behavior corresponds to techniques associated with Defense Evasion and potentially Privilege Escalation depending on the specific outcome achieved by the symlink swap. The exploitation relies heavily on precise timing and filesystem manipulation capabilities available within the Windows environment where ImageMagick is deployed.
To mitigate this risk, organizations must immediately upgrade ImageMagick to version 7.1.2-30 or later, which addresses these race conditions through improved atomicity in path resolution and policy enforcement logic. Additionally, administrators should enforce strict file permissions on directories containing sensitive data to limit the impact of any potential symlink manipulation by unprivileged users. Implementing application-level sandboxing for ImageMagick processes can further reduce the blast radius if a vulnerability is exploited. Regular auditing of image processing workflows and restricting input sources to trusted entities are also recommended defensive measures to minimize exposure to such race condition attacks.