CVE-2026-78416 craftcms CVE debrief

Who should care

Defenders and administrators of systems using Craft CMS versions 4.0.0-RC1 to 4.18.1 and 5.0.0-RC1 to 5.10.5 should assess exposure and apply patches or mitigations. This includes operators, platform administrators, vulnerability management teams, and security teams responsible for these systems.

Why it matters

CVE-2026-78416 is an authenticated remote code execution vulnerability in Craft CMS, allowing command execution as the PHP/web user. Defenders should prioritize verifying exposure and applying patches or mitigations, focusing on systems with Craft CMS versions 4.0.0-RC1 to 4.18.1 and 5.0.0-RC1 to 5.10.5.

• Command execution as PHP/web user
• Potential system compromise or data breach
• Verification of exposure and patch application priority

Technical summary

The vulnerability exists in control panel element-search condition handling due to a JSON cleanse bypass in condition.config, allowing Yii behavior/event configuration keys to be interpreted after decoding. This enables command execution as the PHP/web user in Craft CMS versions from 4.0.0-RC1 before 4.18.2 and from 5.0.0-RC1 before 5.10.6. Affected product deployments should be identified, and defenders should prioritize verifying exposure and applying patches or mitigations, focusing on systems with Craft CMS versions 4.0.0-RC1 to 4.18.1 and 5.0.0-RC1 to 5.10.5.

Defensive priority

Defenders should prioritize verifying exposure and applying patches or mitigations, focusing on systems with Craft CMS versions 4.0.0-RC1 to 4.18.1 and 5.0.0-RC1 to 5.10.5.

Recommended defensive actions

• Verify Craft CMS version and check for exposure
• Apply patches or mitigations for affected versions
• Monitor systems for potential exploitation attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD detail page provide information on the vulnerability, while GitHub references offer source code and release information. However, details on exploitation, victims, or business impact are not provided.

Sources and 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.