CVE-2026-53465: ImageMagick Buffer Overflow Vulnerability

CVE-2026-53465 Overview

CVE-2026-53465 is a heap buffer overflow vulnerability in ImageMagick, a widely used open-source image manipulation library. The flaw exists in the SF3 encoder and triggers when ImageMagick processes a crafted multi-frame image. Encoding such an input causes a heap buffer over-write, classified under [CWE-122] Heap-based Buffer Overflow.

The vulnerability affects ImageMagick versions prior to 7.1.2-25 and has been patched in version 7.1.2-25. Exploitation requires local attack vector access and produces high availability impact, with no confidentiality or integrity impact reported.

Critical Impact

A crafted multi-frame image processed by the SF3 encoder writes beyond an allocated heap buffer, corrupting memory and crashing the ImageMagick process or any application embedding the library.

Affected Products

• ImageMagick versions prior to 7.1.2-25
• Applications and services that embed vulnerable ImageMagick builds
• Image processing pipelines invoking the SF3 encoder

Discovery Timeline

• 2026-06-10 - CVE-2026-53465 published to NVD
• 2026-06-10 - Last updated in NVD database

Technical Details for CVE-2026-53465

Vulnerability Analysis

The vulnerability resides in ImageMagick's SF3 encoder path. When the encoder processes a multi-frame image whose frame metadata or pixel layout differs from the encoder's allocation assumptions, the resulting write operation extends past the bounds of a heap-allocated buffer. The over-write corrupts adjacent heap metadata and data structures.

Because ImageMagick is commonly invoked by server-side image processors, web applications, and command-line tooling, a crafted file delivered through normal image-handling workflows reaches the vulnerable encoder. The primary outcome is process termination and denial of service, consistent with the high availability impact reported.

The attack surface is local rather than network-reachable because the SF3 encoder is invoked when a user or service explicitly requests SF3 encoding of a multi-frame source. No authentication or user interaction is required once the file reaches the encoder.

Root Cause

The SF3 encoder allocates a heap buffer sized from one set of frame attributes but writes encoded data using a different size derived from a second set of attributes in the multi-frame input. Missing bounds validation between these two paths allows the write to exceed the allocation.

Attack Vector

An attacker supplies a crafted multi-frame image to a workflow that invokes ImageMagick's SF3 encoder. When the encoder runs, the heap buffer over-write occurs in the process address space hosting ImageMagick. See the GitHub Security Advisory for the maintainer's technical description.

No verified proof-of-concept code is published. Refer to the
upstream advisory for the encoder code path and patch diff.

Detection Methods for CVE-2026-53465

Indicators of Compromise

• Unexpected crashes or SIGABRT / SIGSEGV signals from convert, magick, or applications linking libMagickCore
• Heap corruption messages such as free(): invalid pointer or malloc(): corrupted top size in process logs
• Presence of unusual multi-frame image inputs targeting the SF3 output format

Detection Strategies

• Inventory installed ImageMagick versions across endpoints, build agents, and container images, flagging any version earlier than 7.1.2-25
• Monitor image processing services for abnormal termination correlated with SF3 encoding requests
• Inspect application logs for ImageMagick errors referencing the SF3 coder module

Monitoring Recommendations

• Enable core dump collection on hosts running ImageMagick to capture evidence of heap corruption
• Alert on repeated crashes of image conversion workers within short time windows
• Track command-line invocations that specify SF3 as the output format from untrusted input sources

How to Mitigate CVE-2026-53465

Immediate Actions Required

• Upgrade ImageMagick to version 7.1.2-25 or later on all systems
• Rebuild and redeploy container images and packages that bundle ImageMagick
• Audit image processing workflows that accept untrusted multi-frame inputs

Patch Information

The issue is fixed in ImageMagick 7.1.2-25. Patch details and the corrected SF3 encoder logic are documented in the GitHub Security Advisory GHSA-44cp-c3ww-9rv5. Distribution maintainers should track downstream backports for long-term support branches.

Workarounds

• Disable the SF3 coder through ImageMagick's policy.xml until patching is complete
• Reject multi-frame inputs in upstream validation layers when SF3 output is requested
• Run ImageMagick in a sandboxed, resource-limited process to contain crashes

# /etc/ImageMagick-7/policy.xml - disable the SF3 coder
<policymap>
  <policy domain="coder" rights="none" pattern="SF3" />
</policymap>