CVE-2026-3534: brainstormforce astra Cross-site Scripting

Vulnerability summary

CVE-2026-3534 is a medium (CVSS 6.4) Cross-site Scripting vulnerability in brainstormforce astra. EPSS estimates a 0.36% chance of exploitation in the next 30 days, higher than 28.5% of scored vulnerabilities. Fixed in 4.12.4.

Timeline

1. 11-03-2026
   PublishedVulnerability first disclosed.
2. 08-04-2026
   Last modifiedVulnerability information updated.

Description

The Astra theme for WordPress is vulnerable to Stored Cross-Site Scripting via the `ast-page-background-meta` and `ast-content-background-meta` post meta fields in all versions up to, and including, 4.12.3. This is due to insufficient input sanitization on meta registration and missing output escaping in the `astra_get_responsive_background_obj()` function for four CSS-context sub-properties (`background-color`, `background-image`, `overlay-color`, `overlay-gradient`). This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.