CVE-2026-49953

Discuz! X5.0 (builds 20260320–20260610) contains a CAPTCHA bypass vulnerability where limited complexity and predictable character sets in generated CAPTCHA images enable unauthenticated remote attackers to reliably predict challenge text via OCR, bypassing protections on login, registration and ...

CVE-2026-49953 Discuz! X5.0 CAPTCHA Bypass via Predictable Character Set

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...