CVE-2026-53461: ImageMagick ICON Decoder Out-of-Bounds Write (CVSS 7.5)

Technical summary

The vulnerability stems from an incorrect loop implementation in ImageMagick's ICON decoder (CWE-787: out-of-bounds write). The decoder fails to enforce proper boundary checks when processing ICON image headers or data structures, permitting heap buffer overflow. While the immediate consequence documented is denial of service via crash, out-of-bounds heap writes can potentially be leveraged for memory disclosure or code execution depending on heap layout, allocator behavior, and attack sophistication. The flaw is present in both the 6.9.x legacy and 7.x current codebases but has been patched in 6.9.13-50 and 7.1.2-25 respectively.

Business impact

Any organization or service deploying ImageMagick for image processing workflows faces availability risk. Web services, content management systems, image thumbnail generators, and automated image conversion pipelines become crash-prone when exposed to untrusted ICON files. Repeated crashes degrade user experience and service uptime. While code execution has not been publicly demonstrated, the out-of-bounds write primitive is a memory safety defect that warrants urgent patching in defense-in-depth strategies. Downstream projects embedding ImageMagick inherit this risk.

Affected systems

ImageMagick versions 6.9.13-49 and earlier (6.9.x branch) and 7.1.2-24 and earlier (7.x branch) are vulnerable. Any deployment accepting untrusted image input—whether via web upload, API, batch processing, or automation—is at risk. This includes containerized environments, cloud image services, and embedded systems using ImageMagick for image manipulation. Verify your installed version against the patched releases: 6.9.13-50 or 7.1.2-25 and later.

Exploitability

The vulnerability requires no authentication or user interaction to trigger; a remote attacker can craft a malicious ICON file and submit it for processing. The attack vector is network-accessible and has low complexity. Public exploitation is currently limited to denial-of-service (application crash). However, the underlying out-of-bounds write is a memory safety defect that skilled attackers might extend toward information disclosure or code execution through heap spray or similar techniques, particularly in specific allocator configurations or with ASLR disabled. The CVSS 3.1 score of 7.5 (HIGH) reflects the availability impact; confidentiality and integrity scores are currently zero.

Remediation

Upgrade ImageMagick to version 6.9.13-50 or later (6.9.x users) or version 7.1.2-25 or later (7.x users). Verify the upgrade by checking the version output of the 'identify' or 'convert' command. For organizations unable to patch immediately, implement input validation to reject untrusted ICON files at the application layer, disable ICON decoding if not required, or isolate ImageMagick processing in restricted environments (sandboxing, containers with limited privileges). Monitor logs for repeated crashes tied to image processing.

Patch guidance

Apply the vendor patch for your branch without delay. ImageMagick 6.9.13-50 and 7.1.2-25 contain the fix for the ICON decoder loop logic. Test patches in a staging environment to confirm compatibility with your image pipelines. If you maintain a Docker image or container with ImageMagick, rebuild from an updated base layer or install the patched version explicitly. Document the patch version in your configuration management system to track remediation status across your infrastructure.

Detection guidance

Monitor application logs and system coredumps for segmentation faults or abort signals coinciding with image processing tasks. Watch for ICON files (*.ico) in upload directories or processing queues, especially from untrusted sources. Network IDS/IPS rules can flag suspicious ICON payloads if signatures are available from your security vendor. Establish baseline metrics for ImageMagick process crashes; a spike in crashes after ICON file exposure is a red flag. Implement file-type validation on entry points to reject ICON files if they are not legitimately required.

Why prioritize this

Although the immediate impact is denial of service, the underlying out-of-bounds write (CWE-787) is a critical memory safety defect. ImageMagick's ubiquity in web applications, media processing, and automation frameworks amplifies exposure. The CVSS 7.5 score and network attack vector justify rapid patching. Organizations processing user-supplied images must prioritize this update to maintain service availability and reduce risk of future exploitation of the same vulnerability class.

Risk score, explained

CVSS 3.1 score of 7.5 (HIGH) is driven by: Attack Vector=Network (AV:N), Attack Complexity=Low (AC:L), no Privileges Required (PR:N), no User Interaction (UI:N), Scope=Unchanged (S:U), Availability=High (A:H), and zero impact to Confidentiality and Integrity. The score reflects the ease of exploitation and immediate availability impact. The score does not account for potential future escalation to code execution, which would likely raise severity further.

Frequently asked questions