Security readout for executives and security teams
Plain-English summary
OpenNMS admin pages lacked CSRF protection, allowing an attacker to trick a logged-in administrator into granting a normal user the ROLE_ADMIN role. The issue needs admin interaction but could lead to full administrative control of the OpenNMS instance.
Executive priority
Treat as high priority for OpenNMS environments because successful exploitation can convert a normal account into an administrator. Prioritize systems managing critical monitoring, infrastructure visibility, or operational alerting.
Technical view
CVE-2021-25931 is CWE-352 CSRF in `/opennms/admin/userGroupView/users/updateUser`. A forged request from an attacker-controlled site can cause an authenticated admin browser to update user roles. Affected ranges include OpenNMS Horizon through 27.1.0-1 and specified Meridian 2015, 2019, and 2020 releases.
Likely exposure
Exposure is likely where affected OpenNMS Horizon or Meridian versions are deployed and administrators browse external content while authenticated to OpenNMS. Internet-facing or broadly reachable admin interfaces increase practical risk.
Exploitation context
The source bundle does not show CISA KEV listing or confirmed active exploitation. Exploitation requires convincing an authenticated administrator to visit attacker-controlled content while their OpenNMS session can submit the vulnerable request.
Researcher notes
Evidence identifies a CSRF flaw and vulnerable endpoint, but the prompt bundle does not provide exploit-in-the-wild confirmation. Focus validation on version inventory, role-change audit trails, and confirming CSRF protections in the relevant patched code path.
Mitigation direction
- Identify OpenNMS Horizon and Meridian versions in use.
- Upgrade to a non-affected release following OpenNMS vendor guidance.
- Restrict administrative UI access to trusted networks or VPN users.
- Review vendor commits and advisory references for CSRF fix details.
- Educate administrators to avoid untrusted links while logged in.
Validation and detection
- Confirm whether deployed versions fall within the affected ranges.
- Review role memberships for unexpected ROLE_ADMIN assignments.
- Check administrative access logs around user role changes.
- Verify the updateUser flow includes CSRF protection after remediation.
- Confirm admin UI is not broadly exposed.
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-2021-25931 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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:N/UI:R/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/OpenNMS/opennms/commit/607151ea8f90212a3fb37c977fa57c7d58d26a84CVE reference · x_refsource_MISC
- https://github.com/OpenNMS/opennms/commit/eb08b5ed4c5548f3e941a1f0d0363ae4439fa98cCVE reference · x_refsource_MISC
- https://www.whitesourcesoftware.com/vulnerability-database/CVE-2021-25931CVE reference · x_refsource_MISC
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.