CVE-2026-49952 Details
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.
A vulnerability in Discuz! X5.0, specifically in releases from 20260320 to 20260501, allows unauthenticated remote attackers to bypass authentication and gain unauthorized access to database backup and restore functionalities. This is achieved by exploiting a shared cryptographic key between UCenter integration and the database backup API in dbbak.php. Attackers can inject crafted payloads through the username parameter during login, manipulating the encryption process to obtain a validly signed token. This token is then used to bypass authorization for database operations, with the added ability to trigger a race condition to impersonate any user.
Users are advised to upgrade to Discuz! X5.0 version 20260510 or later.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jun 15, 2026CISA-ADP
Assessed Jun 15, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| http://seclists.org/fulldisclosure/2026/Jun/3 | CVE | |
| https://gitee.com/Discuz/DiscuzX/commit/9962dad52c4c6999dabaf91ecd70377c680ff3c6 | [email protected] | Source CodeVendor |
| https://karmainsecurity.com/chaining-bugs-in-discuz-from-race-condition-to-rce | [email protected] | BundleExploitRemedyTechnical Analysis |
| https://karmainsecurity.com/KIS-2026-09 | [email protected] | AdvisoryExploitRemedy |
| https://www.vulncheck.com/advisories/discuz-x5-0-authentication-bypass-via-dbbak-php-encryption-oracle | [email protected] | AdvisoryBundle |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-323 | Reusing a Nonce, Key Pair in Encryption | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Discuz! | >= 20260320, <= 20260501 |
CPE
Remediation
| |
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 16, 2026 | CVE Modified | CVE |
| Jun 15, 2026 | New CVE Received | [email protected] |