CVE-2026-53465: ImageMagick Heap Buffer Overflow in SF3 Encoder

Technical summary

CVE-2026-53465 is a heap buffer overflow (CWE-787) in ImageMagick's SF3 encoder that occurs during the encoding of maliciously constructed multi-frame images. The vulnerability stems from improper bounds checking (CWE-122) when writing to heap memory. An attacker with local access can craft a multi-frame image file that, when processed by ImageMagick 7.1.2-24 or earlier, causes out-of-bounds memory writes. The attack vector is local with low complexity and no privilege requirements, resulting in denial of service through application or service termination. The patch is available in version 7.1.2-25.

Business impact

Organizations relying on ImageMagick for batch image processing, content management systems, or automated image workflows face potential service disruptions. A crafted image file could crash imaging services, interrupt batch jobs, or destabilize systems that process untrusted or user-supplied image content. The impact is primarily availability-focused rather than confidentiality or integrity, but repeated exploitation could constitute a denial-of-service vector against image processing pipelines. Web-facing services that accept multi-frame image uploads are at higher risk of encountering malicious payloads.

Affected systems

ImageMagick versions prior to 7.1.2-25 are affected. This includes all 7.1.2 releases up to and including 7.1.2-24, as well as earlier major versions. The vulnerability is triggered specifically during SF3 encoding operations, so systems that process multi-frame images or accept untrusted image uploads are most exposed. Container environments, cloud-native image processing services, and any automated workflows that handle user-supplied images should be prioritized for assessment and patching.

Exploitability

Exploitation requires local access and the ability to supply a crafted multi-frame image to the vulnerable ImageMagick process. The attack has low complexity—no special privileges, authentication, or user interaction is needed beyond the initial file placement. However, practical exploitation depends on the application context: services that accept arbitrary image uploads from untrusted sources face higher risk than isolated systems processing known-good images. The vulnerability does not appear to enable remote code execution, limiting impact to denial of service. No public exploit code or active exploitation has been documented at this time.

Remediation

Upgrade ImageMagick to version 7.1.2-25 or later. Organizations should verify their installation method (package manager, container image, compiled from source) and apply the appropriate patch. For systems unable to patch immediately, implement input validation to reject or sanitize suspicious multi-frame image files, restrict processing of SF3-encoded images if not required, and isolate image processing services to limit blast radius. Consider deploying file-type validation upstream to filter unexpected image formats.

Patch guidance

Verify your current ImageMagick version using `identify -version` or `convert -version`. If the version is 7.1.2-24 or earlier, update to 7.1.2-25 or later. For package-managed systems, use your distribution's package manager (apt, yum, etc.). For Docker or container users, pull an updated base image or rebuild from a newer ImageMagick release. For source builds, obtain the patched release from the official ImageMagick repository, recompile, and redeploy. Test image processing workflows after patching to ensure compatibility with your application stack.

Detection guidance

Monitor ImageMagick process crashes or service interruptions correlated with multi-frame image processing. Check logs for segmentation faults or buffer overflow signals (SIGSEGV) during encode operations. Network and endpoint detection tools can alert on abnormal termination of convert or identify processes. In environments accepting user uploads, correlate suspicious image file attributes (unusual frame counts, malformed headers) with subsequent service failures. Endpoint Detection and Response (EDR) solutions may flag heap corruption attempts if configured to monitor memory access violations.

Why prioritize this

This vulnerability merits timely patching because it affects a foundational, widely-deployed image processing library with CVSS 6.2 (MEDIUM severity). While impact is limited to denial of service, the low attack complexity and local-access requirement mean that any organization accepting or processing untrusted images is exposed. The issue is not yet on the CISA Known Exploited Vulnerabilities (KEV) list, providing a window to patch proactively before weaponization. Organizations with image-heavy workflows, user-generated content platforms, or automated media processing should prioritize this update within their standard patching cadence.

Risk score, explained

The CVSS 3.1 score of 6.2 reflects a MEDIUM-severity vulnerability. The score is driven by high availability impact (heap buffer overflow can crash the application) but mitigated by local-only attack vector (AV:L), low complexity (AC:L), and no impact to confidentiality or integrity. The lack of network attack vector and requirement for local file access prevent this from achieving a higher severity rating, though in cloud or shared-tenant environments, local access may be easier to obtain.

Frequently asked questions