CVE-2026-56592 is a medium severity (CVSS 6.5) improper authentication flaw in HCL BigFix Service Management. Inadequate account lockout lets an unauthenticated attacker run sustained brute force attempts against the login page. Apply the fix named in HCL bulletin KB0133917.
What's affected
The record lists HCL BigFix Service Management and gives no version range. HCL's security bulletin for BigFix Service Management, which covers multiple vulnerabilities, carries the affected versions and the fix. The page needs JavaScript to display, so I could not read it for this post.
The same bulletin covers two records in this series, CVE-2026-56590 and CVE-2026-56592, both published on 18 September 2026.
The CVSS vector is AV:N/AC:L/PR:N/UI:N with low confidentiality and availability impact. No account is needed to attempt the attack, so exposure of the login page to the internet is the factor that matters most.
How to check if you're exposed
HCL publishes the fixed version and affected range in its security bulletin, which needs a browser to read. Open the bulletin linked below and compare it with your installed version.
- Find your BigFix Service Management version in the admin console or deployment records.
- Check whether the login page is reachable from the internet.
- Review authentication logs for long runs of failed logins from the same source or against the same account.
What to do now
- Open HCL bulletin KB0133917 and find the fixed version for your release.
- Apply the update in a test environment, then in production.
- Put the login page behind a VPN, a reverse proxy or an allowlist, so it is not open to the whole internet.
- Add rate limiting at your proxy or web application firewall for the login path.
- Turn on multi factor authentication for accounts if the product supports it, and review failed login alerts.
Why it matters
The weakness is CWE-307, improper restriction of excessive authentication attempts. Without a lockout or delay, an attacker can guess passwords as fast as the server answers. Weak or reused passwords then fall in a matter of time.
Lockout design is a balance, since locking accounts too eagerly lets an attacker deny service to real users. Throttling by source, increasing delays and multi factor authentication give protection without those side effects. The record is not in CISA's Known Exploited Vulnerabilities catalog.
Quick check
Does a strong password solve this?
It helps a lot, but the product should still limit attempts. Combine long unique passwords with rate limits and multi factor authentication.
Sources
Last reviewed: 19 October 2026.
