CVE-2026-46693 Overview
CVE-2026-46693 is a race condition vulnerability in ImageMagick, the free and open-source image manipulation toolkit. The flaw affects the magick -distribute-cache service, which provides distributed pixel cache functionality across networked ImageMagick instances. An attacker who can connect to the distributed cache service can hijack a file descriptor inside the server process when a specific race window is triggered. The vulnerability is classified under [CWE-362] (Concurrent Execution using Shared Resource with Improper Synchronization). It affects ImageMagick versions prior to 6.9.13-48 and 7.1.2-23, and has been patched in those releases.
Critical Impact
An authenticated local attacker capable of reaching the distributed-cache service can hijack a server-side file descriptor, leading to confidentiality exposure of data accessible through that descriptor.
Affected Products
- ImageMagick versions prior to 6.9.13-48
- ImageMagick versions prior to 7.1.2-23
- Systems exposing the magick -distribute-cache service
Discovery Timeline
- 2026-06-10 - CVE-2026-46693 published to NVD
- 2026-06-10 - Last updated in NVD database
Technical Details for CVE-2026-46693
Vulnerability Analysis
ImageMagick supports a distributed pixel cache through its magick -distribute-cache mode. This service listens for connections from peer ImageMagick processes and exchanges image data over sockets. The server tracks per-client state, including file descriptors used for cache I/O.
The vulnerability stems from a race condition in how the server manages descriptors for concurrent client sessions. When two operations interleave in an unsynchronized window, an attacker connection can assume control of a descriptor opened on behalf of another session. The result is descriptor hijacking inside the server process, allowing the attacker session to operate on a resource it was never authorized to access.
The attack requires local access and high privileges, and the complexity is high because the attacker must reliably win the race. Impact is limited to confidentiality, with no integrity or availability effect reported.
Root Cause
The root cause is improper synchronization around shared file descriptor state in the distributed-cache server [CWE-362]. Concurrent client handling does not adequately serialize descriptor assignment, so a descriptor created for one session can be referenced by a different session during the unguarded interval.
Attack Vector
An attacker with the ability to connect to the magick -distribute-cache endpoint initiates a session in parallel with legitimate traffic. By repeatedly triggering operations that allocate or operate on descriptors, the attacker attempts to land their request inside the race window. On success, the attacker session inherits a descriptor opened in another client context and can read its contents through normal cache protocol operations. No exploit code is publicly available. Technical details are documented in the GitHub Security Advisory GHSA-4g75-9r48-jf92.
Detection Methods for CVE-2026-46693
Indicators of Compromise
- Unexpected processes invoking magick -distribute-cache or listening sockets owned by ImageMagick on non-standard ports.
- Multiple concurrent client connections to the distributed-cache service from the same local user within tight time windows, indicative of race exploitation attempts.
- Access to files or image assets by the ImageMagick server process that fall outside the expected workload.
Detection Strategies
- Inventory hosts running ImageMagick and identify any process running with the -distribute-cache flag using process telemetry.
- Compare installed ImageMagick versions against the fixed releases 6.9.13-48 and 7.1.2-23 using package management queries.
- Audit local accounts permitted to reach the cache service and flag unexpected connection patterns in host logs.
Monitoring Recommendations
- Monitor for new listener sockets created by magick or convert binaries and alert on persistent listeners.
- Track file descriptor usage and file access patterns of the ImageMagick server process for anomalies.
- Log all invocations of ImageMagick CLI tools with the -distribute-cache argument in shell and process auditing.
How to Mitigate CVE-2026-46693
Immediate Actions Required
- Upgrade ImageMagick to version 6.9.13-48 or 7.1.2-23 or later on all systems.
- Disable or stop any running magick -distribute-cache services that are not strictly required.
- Restrict network and local access to the distributed-cache port using host firewall rules so only trusted peers can connect.
Patch Information
The ImageMagick maintainers released fixes in versions 6.9.13-48 and 7.1.2-23. Patch notes and code changes are referenced in the ImageMagick Security Advisory GHSA-4g75-9r48-jf92. Verify the installed version with magick -version after upgrading.
Workarounds
- Do not start the distributed-cache server unless required by the workload. Avoid passing -distribute-cache to the magick binary in production scripts.
- Bind the distributed-cache listener exclusively to loopback or a dedicated, firewalled management interface to prevent untrusted local users from connecting.
- Run ImageMagick under a dedicated low-privilege account whose accessible files are limited to the minimum required dataset, reducing the value of any hijacked descriptor.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
