CVE-2026-78531 ThemeREX CVE debrief

Who should care

Defenders responsible for WordPress installations using the Jacqueline theme should assess exposure and prioritize remediation.

Why it matters

CVE-2026-78531 is a critical unauthenticated PHP Object Injection vulnerability in Jacqueline theme versions <= 2.22, requiring immediate attention from defenders to verify exposure and prioritize remediation.

• Potential for code execution on vulnerable systems
• Possible data breaches due to injection vulnerability
• Required verification of system exposure and remediation

Technical summary

The Jacqueline theme versions <= 2.22 has an unauthenticated PHP Object Injection vulnerability. This vulnerability allows potential code execution on vulnerable systems and possible data breaches. Defenders should prioritize verifying exposure and remediation for this critical vulnerability.

Defensive priority

Defenders should prioritize verifying exposure and remediation for this critical vulnerability.

Recommended defensive actions

• Verify exposure of Jacqueline theme versions <= 2.22
• Assess potential impact on systems using the vulnerable theme
• Prioritize remediation or mitigation of the vulnerability

Evidence notes

The vulnerability has a CVSS score of 9.8 and is considered critical. Evidence is limited to public CVE metadata and NIST NVD detail page assessments. Defenders should verify exposure and prioritize remediation based on available information. The CVE record was published on 2026-10-10T20:16:46.830Z and has not been modified since then.

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.