CVE-2026-21806 HCL BigFix Service Management was affected with Admin Session Concurrency vulnerability (CVE-2026-21806)

Low 3.1 Published 18 Sep 2026 Updated 18 Sep 2026

Attackers can hijack administrative sessions due to lack of session concurrency limits, gaining full privileged access to HCL BigFix Service Management.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-21806?

CVE-2026-21806 is a low-severity authentication bypass vulnerability in HCL BigFix Service Management, published on 18 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official 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.

Weakness: CWE-557

Which versions are affected by CVE-2026-21806?

It affects 1 product.

Products include Hcltech Bigfix Service Management.

How do I fix CVE-2026-21806?

No fix has been published for CVE-2026-21806 yet. Limit exposure of the affected software until one is available.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-21806 being exploited?

There is no known exploitation of CVE-2026-21806 in the wild and no public exploit code.

Sources

Also known as GHSA-6qc5-jgrf-h9g7.