CVE-2021-40126

mediumpriority · track · 17EPSS 0.009 · 59 %ileEURUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.87% (59th) EPSS
CVSS 4 · medium
Is it mine?
4 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

EPSS · scored 2026-10-27

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

4.3
010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04mediumAV:N/AC:L/Au:S/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 8 · impact 2.9
v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 1.4
v3.14.3mediumAV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:Nsecondary · FSTEC (BDU) RU
v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:Nsecondary · ENISA EU
v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:Nsecondary · psirt@cisco.com USexploitability 2.8 · impact 1.4
v3.14mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)
v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:Nsecondary · Cisco PSIRT US
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-209USprimaryCWE-209USCWE-210USCWE-210US
05

affected products (4)

Products and version ranges known to be affected.

06

advisories (1)

Vendor and ecosystem advisories describing this.

  • cisco-sa-umbrella-user-enum-S7XfJwDECisco Umbrella Email Enumeration Vulnerability2021-11-03csaf · cisco_csafUS

    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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

07

also known as (4)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducisco_csafnvdNVDCVE.orgMITRE
published 2021-11-04modified 2026-06-17
10

references (5)

External citations — patches, advisories, analysis.

scry

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