What is CVE-2026-19856?

CVE-2026-19856 is a medium-severity vulnerability in All In One Seo, classified under CWE-74 IMPROPER NEUTRALIZATION OF SPECIAL ELEMENTS IN OUTPUT USED BY A DOWNSTREAM COMPONENT ('INJECTION'). CVSS score: 6.5/10. Published 2026-10-02.

How severe is CVE-2026-19856?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in All In One Seo

CVE-2026-19856

The All in One SEO WordPress plugin before 5.0.2.1 does not correctly determine which shortcodes are present in content derived from user input before deciding which ones to strip, allowing unauthenticated users to execute arbitrary shortcodes registered on the site. On sites upgraded from older versions the protection is disabled outright, making the issue reachable without any crafted input.

Published 2026-10-02.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

All In One Seo

References

wpscan.com/vulnerability/e35365d3-65de-45a7-9629-17aacd5299c7/ (technical-description, exploit, vdb-entry)

Frequently asked questions

What is CVE-2026-19856?: CVE-2026-19856 is a medium-severity vulnerability in All In One Seo, classified under CWE-74 IMPROPER NEUTRALIZATION OF SPECIAL ELEMENTS IN OUTPUT USED BY A DOWNSTREAM COMPONENT ('INJECTION'). CVSS score: 6.5/10. Published 2026-10-02.
How severe is CVE-2026-19856?: Medium severity. CVSS v3 base score is 6.5 out of 10.