CVE-2026-49952

CRITICAL

Discuz! X5.0 Authentication Bypass via dbbak.php Encryption Oracle

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-49952. PoCs published by passwa11.

AI-analyzed exploit summary This repository contains a functional exploit for CVE-2026-49952, targeting Discuz! X5.0. The exploit demonstrates a remote code execution (RCE) chain involving database export/import, race condition attacks, and admin authentication bypass to achieve a webshell.

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.

Exploits (1)

github WORKING POC
by passwa11 · poc
https://github.com/passwa11/CVE-2026-49952

This repository contains a functional exploit for CVE-2026-49952, targeting Discuz! X5.0. The exploit demonstrates a remote code execution (RCE) chain involving database export/import, race condition attacks, and admin authentication bypass to achieve a webshell.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Complex
Reliability
Racy
Target: Discuz! X5.0
No auth needed
Prerequisites: Pillow · torch · torchvision · access to target Discuz! instance
devstral-2 · analyzed Jun 17, 2026 Full analysis →

Scores

CVSS v3 9.1
EPSS 0.0036
EPSS Percentile 28.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact total

Details

CWE
CWE-323
Status published
Products (1)
Discuz!/Discuz! X5.0 20260320 - 20260501
Published Jun 15, 2026
Tracked Since Jun 16, 2026