CVE-2026-19856: All in One SEO < 5.0.2.1 - Unauthenticated Arbitrary Shortcode Execution via Search Query

Vulnerability summary

CVE-2026-19856 is a medium (CVSS 6.5) Injection vulnerability in unknown all in one seo. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.4% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 5.0.2.1.

Timeline

1. 02-10-2026
   PublishedVulnerability first disclosed.
2. 06-10-2026
   Last modifiedVulnerability information updated.

Description

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.

• CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
• CWE-94Improper Control of Generation of Code ('Code Injection')The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.