CVE-2026-49952 (GCVE-0-2026-49952)
Vulnerability from cvelistv5 – Published: 2026-06-15 18:43 – Updated: 2026-07-28 01:49 X_Open Source
VLAI
EPSS
VEX
Title
Discuz! X5.0 Authentication Bypass via dbbak.php Encryption Oracle
Summary
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.
Severity
9.1 (Critical)
SSVC
Exploitation: poc
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-06-15 19:58 UTC
CWE
- CWE-323 - Reusing a Nonce, Key Pair in Encryption
Assigner
References
5 references
| URL | Tags |
|---|---|
| https://karmainsecurity.com/KIS-2026-09 | technical-description |
| https://karmainsecurity.com/chaining-bugs-in-disc… | exploit |
| https://gitee.com/Discuz/DiscuzX/commit/9962dad52… | patch |
| https://www.vulncheck.com/advisories/discuz-x5-0-… | third-party-advisory |
| http://seclists.org/fulldisclosure/2026/Jun/3 |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Discuz! | Discuz! X5.0 |
Affected:
20260320 , ≤ 20260501
(date)
cpe:2.3:a:discuz:discuzx:*:*:*:*:*:*:*:* |
Date Public
2026-05-09 00:00
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