Critical severity · published Sep 18, 2026
CVE-2026-21806
HCL BigFix Service Management was affected with Admin Session Concurrency vulnerability (CVE-2026-21806)
9.8
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 10% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
HB
Affected product
HB
HCL BigFix Service Management
HCL Software
More from HCL BigFix Service Management
9.8
CVE-2026-56592
HCL BigFix Service Management is affected by multiple security vulnerabilities.
9.8
CVE-2026-56590
HCL BigFix Service Management is affected by multiple security vulnerabilities.
9.8
CVE-2026-67100
HCL BigFix Service Management is affected by multiple security vulnerabilities.
8.1
CVE-2026-67102
HCL BigFix Service Management is affected by multiple security vulnerabilities.
7.4
CVE-2026-67105
HCL BigFix Service Management is affected by multiple security vulnerabilities.