CVE-2021-1311: Cisco Webex Meetings and Cisco Webex Meetings Server Host Key Brute Forcing Vulnerability

Severity: medium (CVSS 5.4 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-01-13 · updated 2026-06-17
Weakness: CWE-307

Description

A 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.

Affected products

Cisco Webex Meetings: before 40.12.0 — fixed in 40.12.0
Cisco WebEx Meetings Server: before 3.0; 3.0, 3.0-maintenance_release1, 3.0-maintenance_release2, 3.0-maintenance_release3, 3.0-maintenance_release4, 4.0 (+3) — fixed in 3.0

How to fix

Upgrade to a fixed version: Cisco Webex Meetings 40.12.0; Cisco WebEx Meetings Server 3.0. Check the vendor advisory for mitigations.

References

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