CVE-2021-28048
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 · uneditedAn overly permissive CORS policy in Devolutions Server before 2021.1 and Devolutions Server LTS before 2020.3.18 allows a remote attacker to leak cross-origin data via a crafted HTML page.
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 confidenceDevolutions Server had an overly permissive CORS (Cross-Origin Resource Sharing) policy that allowed any origin to access resources via cross-origin requests. This misconfiguration enabled a remote attacker hosting a malicious webpage to trick authenticated users into making requests to the vulnerable server, allowing the attacker to read sensitive responses and leak cross-origin data.
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< 2020.3.18< 2021.1CVSS 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
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/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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Determine Devolutions Server versionLocate the installed Devolutions Server version through the administration interface, a version file, or a command-line tool provided by the product. Compare the installed version against the affected ranges: versions below 2020.3.18 or below 2021.1.Affected if The installed version is lower than 2020.3.18 or lower than 2021.1.
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Inspect CORS response headersSend an HTTP request to the Devolutions Server endpoint from a different origin (for example, using curl with an Origin header set to a test domain like http://malicious-site.com) and examine the response headers, specifically the Access-Control-Allow-Origin header.Affected if The Access-Control-Allow-Origin header is set to a wildcard (*) or reflects the origin from the request without restriction.
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Verify CORS policy restrictionsTest multiple different origin domains by sending requests with various Origin header values and check whether the server returns Access-Control-Allow-Origin allowing those origins.Affected if The server accepts and allows cross-origin requests from arbitrary/untrusted origins.
A user is affected if their Devolutions Server version is below 2020.3.18 or below 2021.1, AND the server returns a permissive Access-Control-Allow-Origin header that allows any origin.
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 data2020.3.182021.1
Upgrade Devolutions Server to version 2021.1 or later (or LTS 2020.3.18 or later) to obtain the fixed CORS policy. Alternatively, manually restrict the Access-Control-Allow-Origin header to explicitly trusted domains only.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-28048 — 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-2021-28048 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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