What is the CVSS score of CVE-2021-1221?

CVE-2021-1221 has a CVSS 3.1 base score of 4.1 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N. EPSS exploitation probability: 1.0%.

Webex Meetings CVE-2021-1221

MEDIUM

Improper Input Validation (CWE-20)

2021-02-04 psirt@cisco.com

Cisco Code Injection Webex Meetings Webex Meetings Server

4.1

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-20 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V2 - Validation and Business Logic Input validation, allowlisting
Impact	CVSS score of 4.1 (MEDIUM). Attack characteristics: network attack vector, low complexity, low privileges required, user interaction required.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

No patch listed yet 1.0% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAI

A vulnerability in the user interface of Cisco Webex Meetings and Cisco Webex Meetings Server Software could allow an authenticated, remote attacker to inject a hyperlink into a meeting invitation. Rated medium severity (CVSS 4.1), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-20. A vulnerability in the user interface of Cisco Webex Meetings and Cisco Webex Meetings Server Software could allow an authenticated, remote attacker to inject a hyperlink into a meeting invitation email. The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by entering a URL into a field in the user interface. A successful exploit could allow the attacker to generate a Webex Meetings invitation email that contains a link to a destination of their choosing. Because this email is sent from a trusted source, the recipient may be more likely to click the link. Affected products include: Cisco Webex Meetings, Cisco Webex Meetings Server.

Know when Webex Meetings gets its next vulnerability

Watch products and get an email when something new is published
Check this CVE against your own stack and servers
Exploit and PoC references, threat intelligence from 22 sources

Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

NVD PRIMARY 4.1 MEDIUM

AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

Required

Scope

Changed

Confidentiality

None

Integrity

Low

Availability

None

DescriptionNVD

A vulnerability in the user interface of Cisco Webex Meetings and Cisco Webex Meetings Server Software could allow an authenticated, remote attacker to inject a hyperlink into a meeting invitation email. The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by entering a URL into a field in the user interface. A successful exploit could allow the attacker to generate a Webex Meetings invitation email that contains a link to a destination of their choosing. Because this email is sent from a trusted source, the recipient may be more likely to click the link.

Threat Intelligence Overview

EPSS Score

1.0%

Top 40% exploitable

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC No

EPSS 1.0%

Patch available No

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +1

CVSS: +20

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.