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PatchSiren cyber security CVE debrief

CVE-2026-86421 ImageMagick CVE debrief

CVE-2026-86421 is a memory leak vulnerability in ImageMagick's MSL image decoder. A crafted MSL image can cause memory allocation without proper deallocation, leading to a denial of service. Defenders should assess exposure, prioritize remediation, and verify affected versions. This vulnerability has a medium severity and can be triggered by a malicious MSL image, potentially causing system crashes or instability. It is essential for defenders to review the official advisory and CVE record to validate affected scope, severity, and vendor guidance.

Vendor
ImageMagick
Product
Unknown
CVSS
MEDIUM 6.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-07
Original CVE updated
2026-09-07
Advisory published
2026-09-07
Advisory updated
2026-09-07

Who should care

Defenders responsible for ImageMagick installations, security teams, and vulnerability management teams should assess exposure and prioritize remediation.

Why it matters

CVE-2026-86421 is a medium-severity vulnerability in ImageMagick's MSL image decoder. Defenders should assess exposure, prioritize remediation, and verify affected versions to prevent potential denial of service attacks.

  • Denial of service due to memory exhaustion
  • Potential for system crashes or instability
  • Need for version verification and remediation prioritization

Technical summary

ImageMagick before 7.1.2-30 and 6.9.13-55 contains a memory leak in the MSL image decoder. A crafted MSL image triggers memory allocation without proper deallocation, allowing an attacker to exhaust memory and cause a denial of service. The vulnerability affects ImageMagick installations and can be mitigated by updating to the latest versions or applying vendor-supported patches.

Defensive priority

Medium

Recommended defensive actions

  • Assess exposure to ImageMagick MSL image decoder
  • Prioritize remediation for affected versions
  • Verify affected versions and potential impact

Evidence notes

The CVE record and NVD entry provide details on the vulnerability. However, the affected versions and potential impact require further verification from official sources.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-86421 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-86421

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-86421 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-86421

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.