Preliminary research

Chaining Security Bugs in Discuz! X5.0: from Race Condition to Pre-Auth RCE

AI-collected research leads through 1 October 2026, including a bounded September review of selected social and community sources. Unranked, incomplete, not community-vetted, and subject to change.

The write-up chains cross-context token reuse, a database import race, automated CAPTCHA solving, and an administrative local-file-inclusion flaw into unauthenticated code execution against Discuz! X5.0. It documents the exploit mechanics, patch timeline, and three assigned CVEs.

Record

Published by

karmainsecurity.com

Topic

Server

In the archive

• Collected in the 2026 preliminary research sweep

Related sources

• 178bNsA BtCQzYK02sfhkis0xkDst wPadT3Y YMPZWQ Slides
• Discuz X5.0 RCE proof-of-concept bundle

Tags

• attack-chain
• race-condition
• auth-bypass
• captcha-bypass
• lfi
• rce
• php
• cve
• owasp-a01-2021
• owasp-a03-2021
• owasp-a04-2021

This page is the archive's own catalogue record. The research is the work of karmainsecurity.com, first published at the original source. Preserved copies are kept so the citation survives its host; this one was last captured on 2 October 2026.