CVE-2021-40126

Cisco Umbrella Email Enumeration Vulnerability

MEDIUM
4.3
CVSS Score
Published: November 4, 2021 at 03:36 PM UTC
Updated: June 17, 2026 at 04:06 AM UTC
1 product affected across 1 vendorUmbrella

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Severity
MEDIUM4.3
Exploit prediction
EPSS 0.9%
SSVC
No known exploit

Description

A vulnerability in the web-based dashboard of Cisco Umbrella could allow an authenticated, remote attacker to perform an email enumeration attack against the Umbrella infrastructure. This vulnerability is due to an overly descriptive error message on the dashboard that appears when a user attempts to modify their email address when the new address already exists in the system. An attacker could exploit this vulnerability by attempting to modify the user's email address. A successful exploit could allow the attacker to enumerate email addresses of users in the system.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMcisco
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-210CWE-209

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