CVE-2026-49952
CriticalCVSS 9.1Exploitation Probability (EPSS)
Low risk28th percentile — higher than 28% of all known CVEs
Summary
Discuz! X5.0 versions from 20260320 to 20260501 contain 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, attackers can inject crafted payloads through the username parameter during login.
Risk Assessment
This vulnerability poses a serious risk to organizations, allowing attackers to access sensitive database information and impersonate other users. This could lead to data loss and breaches of user privacy.
Recommendation
It is recommended to update to the latest version of Discuz! X5.0 to mitigate this vulnerability. Additionally, monitoring logs and implementing extra security measures to protect against unauthorized access is advised.
Original NVD description (English source)
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.