PT-2026-49307 · Discuzx · Discuz! X5.0

Egidio Romano · Published 2026-06-15 · Updated 2026-06-15 · CVE-2026-49952

Mitre

CVSS v3.1

9.1

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

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.

Exploit

Fix

Weakness Enumeration

CWE-323

Related Identifiers

CVE-2026-49952

Affected Products

Discuz! X5.0

References · 5

• 🔥 https://karmainsecurity.com/chaining-bugs-in-discuz-from-race-condition-to-rce · Exploit
• https://gitee.com/Discuz/DiscuzX/commit/9962dad52c4c6999dabaf91ecd70377c680ff3c6 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-49952 · Security Note
• https://karmainsecurity.com/KIS-2026-09 · Note
• https://vulncheck.com/advisories/discuz-x5-0-authentication-bypass-via-dbbak-php-encryption-oracle · Note