CVE-2021-39021Network attack vector

Username enumeration via response discrepancies

Published Feb 4, 2022 · Updated Sep 16, 2024

Observable response discrepancies in IBM Guardium Data Encryption Server 5.0.0.2 allow remote attackers to enumerate usernames. The server's unauthenticated request handling returns distinguishable responses for different account states, but IBM has not published the affected endpoint or exact response difference. Network access without authentication is sufficient; the documented consequence is account-name disclosure, with no integrity or availability impact.

CVSS severity5.3
Medium
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Observable response discrepancies in IBM Guardium Data Encryption Server 5.0.0.2 allow remote attackers to enumerate usernames. The server's unauthenticated request handling returns distinguishable responses for different account states, but IBM has not published the affected endpoint or exact response difference. Network access without authentication is sufficient; the documented consequence is account-name disclosure, with no integrity or availability impact.

The record

CVE
CVE-2021-39021
Published
Feb 4, 2022
Updated
Sep 16, 2024
Vendor
IBM
Product
IBM Guardium Data Encryption
Classifications
CWE-203, T1087
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=5.0.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

IBM · IBM Guardium Data Encryptionversion=5.0.0.2

Published CVSS scores

3.7IBMCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
5.0NIST National Vulnerability DatabaseAV:N/AC:L/Au:N/C:P/I:N/A:N
5.3NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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-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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo