CVE-2026-61858 in ImageMagick
Summary
by MITRE • 07/11/2026
ImageMagick before 7.1.2-26 contains a policy bypass vulnerability in the APNG encoder and external delegates due to missing validation checks. Attackers can write files to disallowed paths by bypassing configured policy restrictions through the APNG encoding process.
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Analysis
by VulDB Data Team • 07/11/2026
The vulnerability in ImageMagick versions prior to 7.1.2-26 represents a critical policy bypass flaw that undermines fundamental security controls within the image processing framework. This issue specifically affects the APNG (Animated Portable Network Graphics) encoder and external delegates functionality, where insufficient validation mechanisms allow malicious actors to circumvent configured policy restrictions. The vulnerability stems from inadequate input validation during the encoding process, creating an attack vector that enables unauthorized file system access beyond the intended security boundaries.
The technical implementation of this flaw occurs within the APNG encoding module where the software fails to properly validate file paths and destinations before writing encoded image data. When external delegates are invoked during the encoding process, the system does not sufficiently verify whether the target locations comply with configured policy restrictions. This validation gap allows attackers to manipulate the encoding parameters or delegate commands in such a way that files are written to arbitrary locations on the filesystem, regardless of the security policies that should have prevented such operations. The vulnerability specifically impacts systems where administrators have configured restrictive policies to prevent writing to sensitive directories.
The operational impact of this vulnerability is severe and multifaceted across multiple threat scenarios. Attackers can leverage this bypass to write malicious files to critical system locations, potentially including system binaries, configuration files, or sensitive data directories. The ability to write files to disallowed paths creates opportunities for privilege escalation attacks, persistence mechanisms, and further compromise of affected systems. This vulnerability is particularly dangerous in environments where ImageMagick is used with elevated privileges or in automated processing pipelines where input validation may be insufficient.
Security mitigation strategies should focus on immediate patching to version 7.1.2-26 or later where the policy validation checks have been properly implemented. System administrators should also implement additional monitoring for unusual file system activities, particularly around image processing operations and delegate executions. Network segmentation and privilege restrictions should be enforced to limit the potential impact of successful exploitation attempts. The vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and reflects techniques described in ATT&CK matrix under T1059 (Command and Scripting Interpreter) and T1078 (Valid Accounts) for privilege escalation and persistence. Organizations should also consider implementing mandatory access controls and file system integrity monitoring to detect unauthorized file creation operations that may indicate exploitation attempts.