Vulnerability Description
Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to gain unauthorized access to database backup and restore functionality by exploiting a shared cryptographic key between UCenter integration and the database backup API exposed by dbbak.php. Attackers can inject a crafted payload through the username parameter during login to abuse the encryption oracle in logging_ctl::logging_more(), obtain a legitimately signed token, and use it to bypass authorization for database export and import operations, with the additional ability to trigger a race condition to impersonate arbitrary users.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://gitee.com/Discuz/DiscuzX/commit/9962dad52c4c6999dabaf91ecd70377c680ff3c6
- https://karmainsecurity.com/KIS-2026-09
- https://karmainsecurity.com/chaining-bugs-in-discuz-from-race-condition-to-rce
- https://www.vulncheck.com/advisories/discuz-x5-0-authentication-bypass-via-dbbak
- http://seclists.org/fulldisclosure/2026/Jun/3
FAQ
What is CVE-2026-49952?
CVE-2026-49952 is a vulnerability with a CVSS score of 9.1 (CRITICAL). Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to gain unauthorized access to database backup and restore ...
How severe is CVE-2026-49952?
CVE-2026-49952 has been rated CRITICAL with a CVSS base score of 9.1/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-49952?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.