CVE-2026-21840

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User Enumeration in HCL BigFix Platform

Publication date: 2026-07-14

Last updated on: 2026-07-15

Assigner: HCL Software

Description

HCL BigFix Platform is affected by a user enumeration vulnerability which might allow an attacker, through careful system control and response time monitoring, to perform some level of user enumeration for the BigFix service.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-07-14

Last Modified

2026-07-15

Generated

2026-08-04

AI Q&A

2026-07-15

EPSS Evaluated

2026-08-02

NVD

CVE-2026-21840

EUVD

EUVD-2026-44531

Affected Vendors & Products

Vendor	Product	Version / Range
hcl	bigfix	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-208	Two separate operations in a product require different amounts of time to complete, in a way that is observable to an actor and reveals security-relevant information about the state of the product, such as whether a particular operation was successful or not.

Attack-Flow Graph

Executive Summary

HCL BigFix Platform has a user enumeration vulnerability. This allows an attacker to determine valid usernames by monitoring system responses and timing when interacting with the BigFix service.

Impact Analysis

An attacker could use this to identify valid accounts, potentially enabling further attacks like brute force or social engineering against specific users.

Compliance Impact

The vulnerability allows user enumeration, which could expose user identities. This may impact compliance with GDPR (data protection) and HIPAA (privacy) by increasing the risk of unauthorized data disclosure or privacy violations.

Mitigation Strategies

Apply the latest security patches or updates provided by HCL for BigFix Platform to address the user enumeration vulnerability. Monitor official HCL advisories for mitigation steps and restrict access to the BigFix service to trusted networks or users to reduce exposure.

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