CVE-2021-1311Network attack vector

Host-role takeover via unrestricted host-key guessing

Published Jan 13, 2021 · Updated Nov 12, 2024

Host-key brute forcing in Cisco WebEx Meetings Server allows remote authenticated users to take over the host role during a meeting. The reclaim-host-role feature accepts repeated crafted host-key requests without restricting excessive attempts. Meeting access, including applicable join links and passwords, is required; success transfers host controls and can disrupt meeting integrity and availability.

CVSS severity5.4
Medium
EPSS probability1.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Host-key brute forcing in Cisco WebEx Meetings Server allows remote authenticated users to take over the host role during a meeting. The reclaim-host-role feature accepts repeated crafted host-key requests without restricting excessive attempts. Meeting access, including applicable join links and passwords, is required; success transfers host controls and can disrupt meeting integrity and availability.

The record

CVE
CVE-2021-1311
Published
Jan 13, 2021
Updated
Nov 12, 2024
Vendor
ClamAV
Product
Cisco WebEx Meetings Server
Classifications
CWE-307, T1110
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 12, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ClamAV · Cisco WebEx Meetings Serverversion=n/a

Published CVSS scores

5.5NISTAV:N/AC:L/Au:S/C:N/I:P/A:P
5.4Cisco Systems, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-307Improper Restriction of Excessive Authentication Attempts
T1110Brute Force

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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