Skip to content
EXYS
Back to the CVEs

CVE-2026-21806

9.8, critical

HCL BigFix Service Management is affected by an Administrative Session Concurrency vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
9.8, critical critical CVSS v3.1
EPSS, next 30 days
0.2% higher than 9% of scored CVEs
Exploitation
No public evidence
Published
18 Sept 202629 days ago

Description

HCL BigFix Service Management is affected by an Administrative Session Concurrency vulnerability. The application allows multiple simultaneous authenticated sessions for the same administrative account, which could enable an unauthorized attacker to predict or hijack valid session identifiers. Successful exploitation allows an attacker to compromise affected administrative sessions and execute actions with full privileged user permissions.

Details

Vendor
HCL Software
Product
HCL BigFix Service Management
Weakness
CWE-557 (opens in a new tab)
Status
Analyzed
Updated
14 Oct 2026
Assigner
psirt@hcl.com

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References 1

Advisories 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other HCL Software CVEs

Every HCL Software CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-56590 HCL Software HCL BigFix Service Management Unrestricted Upload of File with Dangerous Type Vulnerability EPSS 0.2% 9.8, critical
  • CVE-2026-56592 HCL BigFix Service Management is affected by an Improper Authentication validation vulnerability related to inadequate account lockouts,… EPSS 0.3% 9.8, critical

Beyond this page

Is CVE-2026-21806 in your network?

This page tells you how dangerous CVE-2026-21806 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

  • EXYS7600 OCELOT

    Find it before attackers do

    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2026-21806 comes with the devices to patch.

    Learn more about EXYS7600 OCELOT

  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

    Learn more about EXYS7950 KONDRA
Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.