CVE-2021-20049Network attack vector

Username enumeration via password change response discrepancy

Published Dec 23, 2021 · Updated Aug 3, 2024

Response discrepancy in SonicWall SMA 100 10.x allows remote attackers to enumerate usernames through password change requests. The password change API returns observably different server responses for valid and invalid usernames, exposing account existence. No authentication or user interaction is required; the consequence is username disclosure, not credential or application-data access.

CVSS severity7.5
High
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Response discrepancy in SonicWall SMA 100 10.x allows remote attackers to enumerate usernames through password change requests. The password change API returns observably different server responses for valid and invalid usernames, exposing account existence. No authentication or user interaction is required; the consequence is username disclosure, not credential or application-data access.

The record

CVE
CVE-2021-20049
Published
Dec 23, 2021
Updated
Aug 3, 2024
Vendor
SonicWall
Product
Secure Mobile Access (SMA) 100 Series
Classifications
CWE-204, CWE-203, T1087
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.2.0.8-37sv and earlier
  2. Affected versionversion=10.2.1.2-24sv and earlier

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SonicWall · Secure Mobile Access (SMA) 100 Seriesversion=10.2.0.8-37sv and earlier; version=10.2.1.2-24sv and earlier

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-204Observable Response Discrepancy
CWE-203Observable Discrepancy
T1087Account Discovery

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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