Cisco Meeting Server Call Bridge Denial of Service Vulnerability

published 2021-10-21 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27309

cvss: 5.9; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.2%; EPSS 1.2% chance of exploitation in 30 days, percentile 67%
public exploits: 0; none known

A vulnerability in an API of the Call Bridge feature of Cisco Meeting Server could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to improper handling of large series of message requests. An attacker could exploit this vulnerability by sending a series of messages to the vulnerable API. A successful exploit could allow the attacker to cause the affected device to reload, dropping all ongoing calls and resulting in a DoS condition.

Patch / fix

fixed in 1

cisco meeting_server 3.2.3

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 y ago (2024-11-07)

Exploit prediction

1.16% chance of exploitation in the next 30 days, higher than 67% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.9	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

Cisco Cisco Meeting Server

Classification

Weakness

CWE-399 Resource Management Errors
CWE-404 Improper Resource Shutdown or Release

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-cms-LAHe8z5v
vendor-advisory

Sources

CVE List CVE-2021-40122
NVD CVE-2021-40122

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Summary