CVE-2026-49952

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 v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
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-php-encryption-oracle
http://seclists.org/fulldisclosure/2026/Jun/3

Configurations

No configuration.

History

16 Jun 2026, 12:16

Type	Values Removed	Values Added
References		() http://seclists.org/fulldisclosure/2026/Jun/3 -

15 Jun 2026, 20:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-15 20:16

Updated : 2026-06-17 10:55

NVD link : CVE-2026-49952

Mitre link : CVE-2026-49952

CVE.ORG link : CVE-2026-49952

JSON object : View

Products Affected

No product.

CWE

CWE-323

Reusing a Nonce, Key Pair in Encryption

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