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Cross-Site Request Forgery (CSRF)Weakness · CWE-352

CVE-2025-27792

HIGH · 7.7 CVSS v4.0 Published 2025-03-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
86/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Opal is OBiBa’s core database application for biobanks or epidemiological studies. Prior to version 5.1.1, the protections against cross-site request forgery (CSRF) were insufficient application-wide. The referrer header is checked, and if it is invalid, the server returns 403. However, the referrer header can be dropped from CSRF requests using `<meta name="referrer" content="never">`, effectively bypassing this protection. Version 5.1.1 contains a patch for the issue.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Opal's CSRF protection relies solely on referrer header validation, which can be bypassed by dropping the referrer header via HTML meta tag (<meta name="referrer" content="never">). This allows attackers to craft malicious pages that perform actions on behalf of authenticated users without triggering the CSRF guard.

MitigationUpgrade to Opal version 5.1.1 or later, which implements proper CSRF protection beyond referrer header checking.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Opal installation and version
    Run 'gem list opal' or check your Gemfile.lock for the opal gem version entry
    Affected if The installed Opal version is below 5.1.1 (versions prior to 5.1.1 are affected)
  2. Locate CSRF configuration
    Examine your Opal application's security configuration files for CSRF protection settings, typically found in authentication or security middleware files
    Affected if CSRF validation is configured to use only referrer header checking without additional token-based protection
  3. Verify referrer-only CSRF implementation
    Search the codebase for CSRF protection logic that validates requests solely by checking the Referer or Origin header, without requiring a CSRF token in the request
    Affected if The application performs CSRF checks exclusively through referrer header validation without secondary token verification
  4. Check for meta referrer tag support
    Review your application's HTML response templates to see if the application or its generated pages set <meta name="referrer" content="never"> or similar referrer-policy headers
    Affected if The application generates or allows pages that can suppress the referrer header, enabling the bypass
  5. Test referrer-header bypass
    Create a test request to an authenticated endpoint while intentionally omitting the Referer header (or setting an empty one) and verify whether the request succeeds without CSRF rejection
    Affected if Requests without a referrer header are accepted for state-changing operations that should require CSRF protection

Your environment is affected if you are running Opal versions prior to 5.1.1 and your CSRF protection relies exclusively on referrer header validation without additional token-based safeguards.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Opal version 5.1.1 or later, which implements proper CSRF protection beyond referrer header checking.

Recommended fix High confidence

5.1.1

  1. Upgrade Opal to version 5.1.1 or later

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation8.0 h
  • Implementation20.0 h
  • Testing12.0 h
  • Review / QA6.0 h
46.0 hours of engineering $8,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-27792 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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