Webex MeetingsApplication · Cisco
CVE-2021-1311
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 vulnerability in the reclaim host role feature of Cisco Webex Meetings and Cisco Webex Meetings Server could allow an authenticated, remote attacker to take over the host role during a meeting. This vulnerability is due to a lack of protection against brute forcing of the host key. An attacker could exploit this vulnerability by sending crafted requests to a vulnerable Cisco Webex Meetings or Webex Meetings Server site. A successful exploit would require the attacker to have access to join a Webex meeting, including applicable meeting join links and passwords. A successful exploit could allow the attacker to acquire or take over the host role for a meeting.
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 confidenceA vulnerability in the reclaim host role feature of Cisco Webex Meetings allows an authenticated attacker with meeting join credentials to brute-force the host key and take over host privileges. The system lacks rate limiting or lockout protection on host key guesses, enabling repeated crafted requests until the correct key is discovered.
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
Webex MeetingsApplication
< 40.12.0
Webex Meetings ServerApplication
< 3.0= 3.0= 4.0CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L
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 installed Cisco Webex Meetings versionAccess the Webex Administration site or check the version information in the meeting platform settings. For Cisco Webex Meetings Server, access the admin console and locate the version information under System Info or About section.Affected if The installed version is less than 40.12.0 for Cisco Webex Meetings, or less than 3.0, equal to 3.0, or equal to 4.0 for Cisco Webex Meetings Server.
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Verify reclaim host role feature is accessibleCheck if the 'Reclaim Host' or 'Claim Host' option is available in the meeting client interface for authenticated participants who join with meeting credentials. This feature is typically found in the meeting controls when a host has left or is absent.Affected if The reclaim host role feature is enabled and accessible to authenticated meeting participants.
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Confirm lack of rate limiting on host key attemptsReview Webex meeting server configuration or security settings for any rate limiting, account lockout, or CAPTCHA mechanisms applied to the host key reclamation feature. Check admin documentation or settings panels for 'brute force protection', 'rate limit', or 'lockout' configurations related to host key entry.Affected if No rate limiting, account lockout after failed attempts, or CAPTCHA is configured or enforced for host key guesses in the reclaim host process.
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Inspect logs for host key brute-force activityReview Webex meeting server logs, security logs, or audit logs for repeated failed host key attempts from the same source or user session. Look for patterns of consecutive failed reclamation attempts.Affected if Logs show repeated failed host key reclamation attempts without triggering lockout or throttling.
You are affected if your Cisco Webex Meetings version is below 40.12.0 (or Webex Meetings Server is version 3.0 or 4.0 or below 3.0) AND the reclaim host role feature is accessible to authenticated users without brute-force protection such as rate limiting or account lockout.
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 data3.040.12.0
Implement brute-force protection mechanisms such as rate limiting, account lockout after failed attempts, or CAPTCHA on the host key reclamation feature. Apply vendor-provided patches when available.
Fix this in Webex Meetings
Scoped from the published advisory
- Consultation4.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1311 — 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-2021-1311 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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