CVE-2020-3430 | Cisco Jabber for Windows Protocol Handler Command Injection Vulnerability

A vulnerability in the application protocol handling features of Cisco Jabber for Windows could allow an unauthenticated, remote attacker to execute arbitrary commands. The vulnerability is due to improper handling of input to the application protocol handlers. An attacker could exploit this vulnerability by convincing a user to click a link within a message sent by email or other messaging platform. A successful exploit could allow the attacker to execute arbitrary commands on a targeted system with the privileges of the user account that is running the Cisco Jabber client software.

Published: 2020-09-03 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-3430 is rated Moderate Risk (64.9/100): CVSS High severity, with medium exploitation likelihood (EPSS 3.90%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-3430

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 5.31% 3.90% -1.40%
2 2026-04-26 5.01% 5.31% +0.29%
3 2026-03-18 — 5.01% —

Full EPSS history (19 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-3430

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H 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:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H 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:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
9.3 2.0 HIGH
AV:N/AC:M/Au:N/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
 8.6 10.0 [email protected]

Weakness enumeration for CVE-2020-3430

Affected software / configurations for CVE-2020-3430

Vendor Product Version Raw CPE
cisco jabber >= 12.1, < 12.1.3 cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
cisco jabber >= 12.5, < 12.5.2 cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
cisco jabber >= 12.6, < 12.6.3 cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
cisco jabber >= 12.7, < 12.7.2 cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
cisco jabber >= 12.8, < 12.8.3 cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
cisco jabber >= 12.9, < 12.9.1 cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*

References for CVE-2020-3430

cvelogic Threat Intelligence