CVE-2026-48733 ImageMagick Infinite Loop Denial-of-Service Vulnerability

Technical summary

CVE-2026-48733 is an infinite loop vulnerability in ImageMagick's subimage-search functionality. The flaw exists in versions prior to 6.9.13-49 (legacy branch) and 7.1.2-24 (current branch). It is classified as CWE-835 (Infinite Loop), triggered by maliciously constructed image files. The attack requires local access and user interaction—an unprivileged user must explicitly open or process the crafted image. The vulnerability results in process hang with no memory safety compromise, making it a pure availability issue with CVSS 3.1 score of 4.7 (Medium).

Business impact

For organizations deploying ImageMagick in image processing pipelines, automated thumbnail generation services, or web-based image manipulation tools, this vulnerability can cause service degradation. A single malicious image file submitted through an upload form or API could exhaust a worker thread or container, reducing throughput or triggering cascading restarts. In multi-tenant or SaaS environments where ImageMagick processes user-supplied images, this becomes a lightweight denial-of-service vector. The impact is operational rather than data-exposing, but repeated exploitation could degrade user experience and consume infrastructure resources.

Affected systems

ImageMagick versions 6.9.13-48 and earlier in the 6.9.x branch, and versions 7.1.2-23 and earlier in the 7.x branch are vulnerable. This includes distributions that bundle ImageMagick as a dependency, such as web frameworks and image processing libraries. Both command-line tools and library consumers are affected. Verify your installed version with `convert -version` (command-line) or by checking package metadata in your application's dependency tree.

Exploitability

Exploitability is moderate but requires user or application interaction. An attacker must craft a specific image file and either convince a user to open it with ImageMagick, or ensure it is processed by an application that automatically handles image uploads or conversions. No network vector exists; the attack is local-only. No privilege escalation is required—any unprivileged user can trigger the condition. The barrier to crafting such an image is unknown from public disclosures, and no weaponized proof-of-concept has been widely published. The vulnerability is not listed on the CISA Known Exploited Vulnerabilities (KEV) catalog, suggesting limited active exploitation in the wild to date.

Remediation

Upgrade ImageMagick to version 6.9.13-49 or later if using the 6.9.x series, or to version 7.1.2-24 or later if using the 7.x series. For systems where ImageMagick is a transitive dependency, check your application's package updates and rebuild with patched versions. If immediate patching is infeasible, implement input validation to reject suspicious image files, or isolate ImageMagick processing in sandboxed containers that can be safely terminated if they hang.

Patch guidance

Patches are available as of June 2026. Update via your distribution's package manager (apt, yum, brew, etc.) or download directly from ImageMagick's official repository. Verify the version post-update using `convert -version`. For containerized deployments, rebuild images with the patched version and redeploy. For embedded or statically-linked builds, coordinate with your vendor or rebuild from source. Test patches in a non-production environment first, as updates may occasionally introduce behavioral changes in edge cases.

Detection guidance

Monitor for hung or stuck ImageMagick processes that do not complete within expected timeframes. Check system logs for worker process crashes or restarts following image uploads. If you maintain ImageMagick metrics, look for sustained high CPU usage on a single process without corresponding memory growth (indicative of busy-waiting in a loop). Network-based detection is not applicable due to the local-only nature of the vulnerability. Behavioral baselines on image processing latency can help flag anomalous delays.

Why prioritize this

This vulnerability merits timely but non-emergency patching. Its Medium CVSS score and lack of KEV listing reflect the narrow attack surface and availability-only impact. However, organizations with public-facing image upload services or automated image pipelines should prioritize this within the next 30 days to reduce operational risk. Those processing only trusted, internal images face minimal exposure and may defer patching to their regular update cycle.

Risk score, explained

The CVSS 3.1 score of 4.7 reflects: (1) local-only attack vector, eliminating network risk; (2) high attack complexity, requiring a specially crafted image; (3) requirement for user interaction; (4) no confidentiality or integrity impact; and (5) high availability impact through process denial-of-service. The score is held at Medium rather than High because the attack vector is local and the impact is constrained to individual process availability rather than system-wide outage.

Frequently asked questions