CVE-2026-55167: LDAP Account Manager: WebAuthn authentication challenge is kept in the PHP session
LDAP Account Manager (LAM) is a webfrontend for managing entries (e.g. users, groups, DHCP settings) stored in an LDAP directory. Prior to 9.6, installations with WebAuthn two-factor authentication leave the challenge in the same PHP session after the authentication response is processed. A user who has already completed valid password authentication can therefore retain the same signed WebAuthn ceremony state instead of consuming it once. The practical risk is limited by the requirement for a valid password, the same PHP session, and a valid authenticator signature. This issue is fixed in version 9.6.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
LDAP Account Managerto a version that resolves this vulnerability.Fixed in 9.6
Event History
Frequently Asked Questions
Which deployments are affected?
Installations of LDAP Account Manager before version 9.6 that use WebAuthn two-factor authentication are affected. Deployments without WebAuthn two-factor authentication are not identified as affected by the provided information.
What does an attacker need to exploit this issue?
The attacker needs a valid password, access to the same PHP session, and a valid authenticator signature. The issue involves retaining an already signed WebAuthn ceremony state after the authentication response has been processed.
What should administrators do if they cannot patch immediately?
The provided information does not specify a workaround. Because exploitation requires a valid password, the same PHP session, and a valid authenticator signature, protecting credentials and PHP session access is particularly important until upgrading.
How can administrators remediate the issue?
Upgrade LDAP Account Manager to version 9.6, which fixes the issue.