Security readout for executives and security teams
Plain-English summary
Discuz! X5.0 can mistakenly grant an unauthenticated internet attacker access to database backup and restore functions. Successful abuse could expose or alter sensitive forum data and may enable user impersonation. No user interaction or existing account is required.
Executive priority
Prioritize emergency assessment and remediation of public-facing affected installations. The vulnerability crosses an authentication boundary and could compromise database confidentiality and integrity. If patching cannot occur promptly, restrict the affected functionality and initiate focused log review.
Technical view
CVE-2026-49952 is a CWE-323 authentication bypass caused by shared cryptographic key use between UCenter integration and dbbak.php. The login path can act as an encryption oracle, producing a valid authorization token for database export or import. A related race condition may permit arbitrary-user impersonation. CVSS 4.0 is 9.3.
Likely exposure
Exposure is highest for internet-accessible Discuz! X5.0 deployments running releases dated 20260320 through 20260501. Administrators should verify the precise build and whether the referenced corrective commit is present. The supplied evidence does not establish that every deployment exposes dbbak.php identically.
Exploitation context
Public technical material describes exploitability and vulnerability chaining, but the supplied evidence does not establish active exploitation in the wild. The CVE is not identified as being in CISA KEV. Treat public-facing affected systems as urgent because exploitation requires no authentication or user interaction.
Researcher notes
The bundle supports the encryption-oracle, shared-key, database-operation, and race-condition claims. It identifies affected releases from 20260320 through 20260501 and links a corrective commit, but does not name a fixed release. It also provides no confirmed telemetry showing exploitation in the wild.
Mitigation direction
- Apply the vendor correction represented by the referenced DiscuzX commit after compatibility testing.
- Check Discuz! vendor guidance for a confirmed fixed release and upgrade path.
- Restrict public access to database backup and restore functionality until remediation is verified.
- Protect database backups and rotate exposed credentials if investigation indicates unauthorized access.
Validation and detection
- Inventory Discuz! X5.0 installations and record their exact release dates or commit revisions.
- Confirm whether the referenced corrective commit is incorporated in each deployment.
- Review login activity for anomalous username inputs associated with unexpected backup or restore requests.
- Review database export, import, and user-account activity for unauthorized operations.
- Retest authorization boundaries safely after remediation without using production data.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-323: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupDatabase behavior lookup
The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-49952 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.3 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N——VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N3.95.2VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.3CriticalVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Base CVSS 3.1 score
9.1CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://karmainsecurity.com/KIS-2026-09CVE reference, VulnCheck · technical-description
- https://karmainsecurity.com/chaining-bugs-in-discuz-from-race-condition-to-rceCVE reference, VulnCheck · exploit
- https://gitee.com/Discuz/DiscuzX/commit/9962dad52c4c6999dabaf91ecd70377c680ff3c6CVE reference, VulnCheck · patch
- https://www.vulncheck.com/advisories/discuz-x5-0-authentication-bypass-via-dbbak-php-encryption-oracleCVE reference, VulnCheck · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Reusing a Nonce, Key Pair in Encryption
Reusing a Nonce, Key Pair in Encryption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.