CVE-2017-18271

Vulnerability

The vulnerability resides in the ReadMIFFImage function in coders/miff.c of ImageMagick 7.0.7-16 Q16 x86_64 (2017-12-22). The parser lacks an end-of-file (EOF) check in a loop ([1]), causing an infinite loop when processing a crafted MIFF image file. The issue does not require special configuration; default resource policies such as those in policy.xml still allow the loop to consume CPU time until any user-defined timeout (e.g., 120 seconds in the example) is reached.

Exploitation

An attacker must supply a malicious MIFF file to a user or service that processes images with ImageMagick (e.g., via convert or a web application). No authentication or special privileges are needed; the victim need only run the tool on the file (e.g., convert cpu-exhaustion-ReadMIFFImage /dev/null [1]). The loop executes indefinitely, saturating one CPU core.

Impact

Successfully exploiting this vulnerability causes 100% CPU consumption on one core for up to the configured time resource limit (default 120 seconds). This leads to a denial of service (CPU exhaustion) for the affected system or application. No data corruption, privilege escalation, or data breach occurs.

Mitigation

A fix was implemented in ImageMagick commit [1] and is included in version 7.0.7-17 and later. Users should upgrade to the latest stable release. If upgrading is not possible, resource limits (e.g., time in policy.xml) can reduce exposure, but they do not prevent the loop; no complete workaround is available. The issue is not listed on CISA's Known Exploited Vulnerabilities (KEV) catalog as of publication.