CVE-2020-3471 [Medium] | Input Validation Bypass in Webex Meetings Server

A vulnerability in Cisco Webex Meetings and Cisco Webex Meetings Server could allow an unauthenticated, remote attacker to maintain bidirectional audio despite being expelled from an active Webex session. The vulnerability is due to a synchronization issue between meeting and media services on a vulnerable Webex site. An attacker could exploit this vulnerability by sending crafted requests to a vulnerable Cisco Webex Meetings or Cisco Webex Meetings Server site. A successful exploit could allow the attacker to maintain the audio connection of a Webex session despite being expelled.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.62%	1.73%	+1.11%
2	2025-03-30	1.21%	0.62%	-0.58%
3	2025-03-29	—	1.21%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.62%

1.73%

+1.11%

2025-03-30

1.21%

0.62%

-0.58%

2025-03-29

—

1.21%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
6.5	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	2.8	3.6	[email protected]
6.5	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	2.8	3.6	[email protected]
5.0	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:P/I:N/A:N` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:N) No availability impact.	10.0	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

6.5

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

2.8

3.6

[email protected]

6.5

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

2.8

3.6

[email protected]

5.0

2.0

MEDIUM

AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:N): No availability impact.

10.0

2.9

[email protected]

Affected software / configurations for CVE-2020-3471

Vendor	Product	Version	Raw CPE
cisco	webex_meetings_server	< 3.0	cpe:2.3:a:cisco:webex_meetings_server::::::::
cisco	webex_meetings_server	3.0	cpe:2.3:a:cisco:webex_meetings_server:3.0:maintenance_release2::::::
cisco	webex_meetings_server	3.0	cpe:2.3:a:cisco:webex_meetings_server:3.0:maintenance_release3::::::
cisco	webex_meetings_server	4.0	cpe:2.3:a:cisco:webex_meetings_server:4.0:-::::::
cisco	webex_meetings_server	4.0	cpe:2.3:a:cisco:webex_meetings_server:4.0:maintenance_release1::::::
cisco	webex_meetings_server	4.0	cpe:2.3:a:cisco:webex_meetings_server:4.0:maintenance_release2::::::

References for CVE-2020-3471

URL	Tags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-info-leak-PhpzB3sG	Vendor Advisory

URL

CVE-2020-3471 | Cisco Webex Meetings and Cisco Webex Meetings Server Unauthorized Audio Information Exposure Vulnerability

Exploit prediction scoring system (EPSS) score for CVE-2020-3471

Common vulnerability scoring system (CVSS) metrics for CVE-2020-3471

Weakness enumeration for CVE-2020-3471

Affected software / configurations for CVE-2020-3471

References for CVE-2020-3471