CVE-2026-49952 EXPLOIT
9.1
CRITICAL · CVSS 3.1 · EPSS 3.7% (pctl 89)
Patch early
A public exploit exists.
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.
Scoring
| CVSS | 9.1 (CRITICAL, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| EPSS | 3.65% — more likely to be exploited than 89% of all CVEs |
| Weakness | CWE-323 |
| On CISA KEV | no |
| Public exploit | yes |
| Published | 2026-06-15 |
| Last modified | 2026-06-17 |
Public exploits
| Source | Title | Date |
|---|---|---|
| exploit-db | Discuz! X5.0 - Authentication Bypass | 2026-07-07 |
References
- 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
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