VULNERABILITY INTELLIGENCE

CVE-2026-49953

CVSS score6.9 MEDIUM

EPSS probability0.36%

CISA KEVNot currently listed

Published2026-06-15

Last modified2026-10-25

Description

Discuz! X5.0 releases 20260320 through 20260610 contains a CAPTCHA bypass vulnerability that allows unauthenticated remote attackers to defeat challenge controls by exploiting limited complexity and predictable character sets in generated CAPTCHA images. Attackers can train a custom optical character recognition model against collected CAPTCHA samples to reliably predict challenge text, bypassing protections on login, registration, and other functionality from automated abuse.