CVE-2026-21840 HCL BigFix Platform is affected by a user enumeration vulnerability
An attacker can enumerate valid users on the HCL BigFix Platform by monitoring response times, potentially aiding further targeted attacks.
- 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-2026-21840?
CVE-2026-21840 is a low-severity vulnerability in HCLSoftware HCL BigFix Platform, published on 14 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-208
Which versions are affected by CVE-2026-21840?
How do I fix CVE-2026-21840?
No fix has been published for CVE-2026-21840 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-21840 being exploited?
There is no known exploitation of CVE-2026-21840 in the wild and no public exploit code.
Sources
Also known as GHSA-95qg-pcpr-8wr9.