CVE-2026-49952 | BDVDB-2026-340508 Detail
Discuz!Discuz! X5.0
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.
Impact#
Per CVSS v3.1: confidentiality impact high, integrity impact high, availability impact none. Attack vector: network.
Weaknesses#
- CWE-323 Reusing a Nonce, Key Pair in Encryption
References#
- https://karmainsecurity.com/KIS-2026-09
- https://karmainsecurity.com/chaining-bugs-in-discuz-from-race-condition-to-rce
- https://gitee.com/Discuz/DiscuzX/commit/9962dad52c4c6999dabaf91ecd70377c680ff3c6
- https://www.vulncheck.com/advisories/discuz-x5-0-authentication-bypass-via-dbbak-php-encryption-oracle
- http://seclists.org/fulldisclosure/2026/Jun/3
Exploit#
History#
- Version 1Record published in the CVE List.
- Version 2Most recent update recorded in the CVE List.