CVE-2026-113659: apostrophecms apostrophe Cross-site Scripting

Vulnerability summary

CVE-2026-113659 is a medium (CVSS 6.1) Cross-site Scripting vulnerability in apostrophecms apostrophe. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 26.7% of scored vulnerabilities.

Timeline

1. 20-10-2026
   PublishedVulnerability first disclosed.

Description

ApostropheCMS is an open-source Node.js content management system. Prior to 4.33.0, an unauthenticated attacker can send a crafted link whose query string is automatically parsed by apos.http.parseQuery when an authenticated victim loads a page with the admin bundle. The parser accepts the special __proto__, constructor, and prototype path keys, allowing browser prototype mutation that can reach an unsafe DOM sink and execute script in the victim's session; anonymous visitors do not load the affected admin context. This issue is fixed in version 4.33.0.

• 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.
• CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.