CVE-2026-90995

Summary

A flaw was found in SSSD (System Security Services Daemon). A local attacker with privileges to connect to the PAM (Pluggable Authentication Modules) responder socket can send a specially crafted protocol request. If the pam_app_services configuration is enabled and the service item is omitted from the request, a NULL pointer dereference can occur. This vulnerability leads to a denial of service, causing the PAM responder to crash and disrupt authentication services.

Affected Software

Weaknesses

• CWE-476: NULL Pointer Dereference

Workarounds

To mitigate this issue, avoid configuring pam_app_services in the [pam] section of /etc/sssd/sssd.conf if it is not operationally required. If pam_app_services is configured, remove or comment out the pam_app_services line and restart the sssd service.

Example:

# /etc/sssd/sssd.conf
[pam]
# pam_app_services = app_svc

After modifying the configuration, restart the SSSD service: systemctl restart sssd

Note that restarting the SSSD service may temporarily interrupt authentication and authorization services.

References

• https://access.redhat.com/security/cve/CVE-2026-90995
• https://bugzilla.redhat.com/show_bug.cgi?id=2479464

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