CVE-2026-78265 Nexcess CVE debrief

Who should care

Defenders responsible for The Events Calendar plugin deployments should assess exposure and prioritize remediation.

Why it matters

CVE-2026-78265 is a critical vulnerability in The Events Calendar plugin, potentially allowing unauthenticated PHP Object Injection. Defenders should assess exposure, prioritize remediation, and verify inventory for affected versions.

• Potential for unauthenticated code execution
• Possible impact on data confidentiality and integrity
• Requires verification of affected plugin versions
• Prioritization of remediation efforts

Technical summary

CVE-2026-78265 is an unauthenticated PHP Object Injection vulnerability in The Events Calendar plugin versions <= 6.17.2, with a CVSS score of 9.8.

Defensive priority

High

Recommended defensive actions

• Assess exposure of The Events Calendar plugin versions <= 6.17.2
• Prioritize remediation of affected plugin versions
• Verify inventory for affected plugin versions

Evidence notes

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

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.