Security readout for executives and security teams
Plain-English summary
GreenCMS v2.3 has a high-severity CSRF flaw in its user-creation path. If a logged-in low-privileged user is tricked into interacting with attacker-controlled content, the application may perform an unwanted add-user action, potentially leading to privilege gain.
Executive priority
Treat this as a high-priority application risk where GreenCMS v2.3 is present, especially if administrative functions are reachable. If the product is not in use, priority drops after inventory confirmation.
Technical view
The CVE describes CWE-352 in GreenCMS v2.3, specifically the adduser function of index.php. The CVSS 3.1 vector is AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H, indicating network reachability, low attack complexity, required low privileges, and user interaction.
Likely exposure
Exposure is most likely where GreenCMS v2.3 is deployed and authenticated user management functions are reachable. The supplied affected-product metadata is sparse, so asset owners should verify actual product and version inventory.
Exploitation context
The supplied sources do not show CISA KEV listing or confirmed active exploitation. The attack requires a privileged application context to process a forged request after user interaction, so phishing or malicious links are plausible enabling conditions.
Researcher notes
Evidence is limited to the CVE record and linked GitHub issue. The CVE names GreenCMS v2.3 and adduser in index.php, but the structured affected field does not provide vendor, product, CPE, or fixed-version data.
Mitigation direction
- Check GreenCMS project guidance for a fixed release or official workaround.
- Restrict GreenCMS admin and user-management access to trusted users and networks.
- Review adduser handling for server-side CSRF token validation.
- Use SameSite cookies and reauthentication for sensitive account-management actions.
- Retire or isolate unsupported GreenCMS v2.3 deployments.
Validation and detection
- Inventory internet-facing and internal GreenCMS deployments.
- Confirm whether any instance is running GreenCMS v2.3.
- Review index.php adduser requests for anti-CSRF validation.
- Check access controls around user creation and privilege assignment.
- Review logs for unexpected user creation or privilege changes.
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-352: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. 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 lookupCVE-2020-21366 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
- High
- CVSS
- 8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
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.
CVSS vector scores
1 official scoreWe 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:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H2.15.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/GreenCMS/GreenCMS/issues/115CVE reference
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.
Cross-Site Request Forgery (CSRF)
Cross-Site Request Forgery (CSRF) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.