CephApplication · Redhat
CVE-2020-27839
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 · uneditedA flaw was found in ceph-dashboard. The JSON Web Token (JWT) used for user authentication is stored by the frontend application in the browser’s localStorage which is potentially vulnerable to attackers via XSS attacks. The highest threat from this vulnerability is to data confidentiality and integrity.
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 · moderate confidenceThe ceph-dashboard stores JSON Web Tokens (JWT) in the browser's localStorage for user authentication, which makes them accessible to malicious scripts via XSS attacks. An attacker who can inject JavaScript into the application can steal these tokens and impersonate users, compromising data confidentiality and integrity.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
CephApplication
< 14.2.17>= 15.2.0, < 15.2.9CVSS 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
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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 checksWork through these to decide whether this CVE applies to you.
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Verify if Ceph Dashboard is enabledRun 'ceph mgr services' or 'ceph dashboard modules' to confirm the dashboard module is activeAffected if Dashboard module is listed as enabled in the output
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Check installed Ceph versionRun 'ceph --version' or 'ceph version' to get the exact version numberAffected if Version is < 14.2.17 OR >= 15.2.0 and < 15.2.9
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Identify Dashboard endpoint URLRun 'ceph mgr services' to retrieve the dashboard URL (usually https://<host>:8443 or similar)Affected if Dashboard URL is accessible, indicating the service is running and potentially affected
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Confirm JWT storage mechanismLog into the Ceph Dashboard, open browser DevTools (F12), go to Application > Local Storage, and check if a JWT token key exists under the dashboard domainAffected if JWT token value is present in localStorage for the dashboard domain (indicates vulnerable storage method)
If Ceph Dashboard is enabled and the installed version falls within < 14.2.17 or >= 15.2.0 to < 15.2.9, and JWT tokens are found in browser localStorage, the environment is affected by this vulnerability.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor data14.2.1715.2.9
Migrate JWT storage from localStorage to httpOnly, secure cookies to prevent XSS-based token theft, and implement appropriate CSRF protection mechanisms.
Fix this in Ceph
Scoped from the published advisory
- Consultation4.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,040.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-27839 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-27839 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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