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ImageMagick's Security Policy Bypass through config/policy-secure.xml via "fd handler" leads to stdin/stdout access

Moderate severity GitHub Reviewed Published Feb 23, 2026 in ImageMagick/ImageMagick • Updated Feb 24, 2026

Package

nuget Magick.NET-Q16-AnyCPU (NuGet)

Affected versions

< 14.10.3

Patched versions

14.10.3
nuget Magick.NET-Q16-HDRI-AnyCPU (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q16-HDRI-OpenMP-arm64 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q16-HDRI-arm64 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q16-HDRI-x64 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q16-HDRI-x86 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q16-OpenMP-arm64 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q16-OpenMP-x64 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q16-OpenMP-x86 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q16-arm64 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q16-x64 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q8-AnyCPU (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q8-OpenMP-arm64 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q8-OpenMP-x64 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q8-arm64 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-Q8-x86 (NuGet)
< 14.10.3
14.10.3
nuget Magick.NET-QMagick.NET-Q16-x8616-x64 (NuGet)
< 14.10.3
14.10.3

Description

The shipped “secure” security policy includes a rule intended to prevent reading/writing from standard streams:

<policy domain="path" rights="none" pattern="-"/>

However, ImageMagick also supports fd: pseudo-filenames (e.g., fd:0, fd:1). This path form is not blocked by the secure policy templates, and therefore bypasses the protection goal of “no stdin/stdout”.

To resolve this, users can add the following change to their security policy.

<policy domain="path" rights="none" pattern="fd:*"/>

And this will also be included in ImageMagick's more secure policies by default.

References

@dlemstra dlemstra published to ImageMagick/ImageMagick Feb 23, 2026
Published by the National Vulnerability Database Feb 24, 2026
Published to the GitHub Advisory Database Feb 24, 2026
Reviewed Feb 24, 2026
Last updated Feb 24, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(2nd percentile)

Weaknesses

Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. Learn more on MITRE.

CVE ID

CVE-2026-25966

GHSA ID

GHSA-xwc6-v6g8-pw2h

Source code

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