CVE-2021-41101
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 · uneditedwire-server is an open-source back end for Wire, a secure collaboration platform. Before version 2.106.0, the CORS ` Access-Control-Allow-Origin ` header set by `nginz` is set for all subdomains of `.wire.com` (including `wire.com`). This means that if somebody were to find an XSS vector in any of the subdomains, they could use it to talk to the Wire API using the user's Cookie. A patch does not exist, but a workaround does. To make sure that a compromise of one subdomain does not yield access to the cookie of another, one may limit the `Access-Control-Allow-Origin` header to apps that actually require the cookie (account-pages, team-settings and the webapp).
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 nginz layer in wire-server sets the CORS Access-Control-Allow-Origin header to allow all subdomains of .wire.com (including wire.com itself). This permissive CORS configuration combined with cookie-based authentication means that an XSS vulnerability in any subdomain can be leveraged to make authenticated API requests to the Wire platform.
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< 2.106.0CVSS 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
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/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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Identify if Wire Server is deployedCheck for the presence of nginz or wire-server components in your environment. Look for configuration directories or services named 'nginz' or 'wire-server'.Affected if Wire Server or its nginz layer is present in your environment
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Locate nginz CORS configurationFind the nginz or nginx configuration files that handle CORS headers. Look for files containing 'Access-Control-Allow-Origin' directives.Affected if A CORS configuration file with Access-Control-Allow-Origin is found
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Inspect Access-Control-Allow-Origin header valueExamine the configured value for Access-Control-Allow-Origin. Look for patterns that match any subdomain of wire.com, such as wildcards, regex patterns, or the literal string '.wire.com'.Affected if The header allows all subdomains of .wire.com or uses a wildcard pattern that includes arbitrary subdomains
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Verify cookie-based authentication is in useCheck if the API endpoints protected by this CORS configuration use cookie-based authentication rather than token-based authentication.Affected if Cookie-based authentication is used for API access through this CORS configuration
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Check Wire Server versionIf possible, determine the installed version of wire-server by querying the service version endpoint or checking package/version files.Affected if The installed version is prior to 2.106.0
You are affected if your environment runs a Wire Server version below 2.106.0 with nginz configured to allow all .wire.com subdomains in Access-Control-Allow-Origin and uses cookie-based authentication.
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.
dbcve · scoped2.106.0
Restrict the Access-Control-Allow-Origin header to only the specific applications that require cookie-based authentication: account-pages, team-settings, and the webapp.
2.106.0
- Upgrade Wire Server to version 2.106.0 or later
- If immediate upgrade is not possible, implement the configuration workaround: Limit the Access-Control-Allow-Origin header to only the applications that require cookie authentication (account-pages, team-settings, and webapp)
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-41101 — 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-2021-41101 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
- No spam, self-promotion, credentials, or personal data