Medium [CVE-2026-90995] Sssd: sssd: local denial of service due to null pointer dereference in pam responder
This medium-severity Red Hat Linux advisory covers CVE-2026-90995 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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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.
This Moderate impact denial of service vulnerability in SSSD's PAM responder requires local access and a non-default `pam_app_services` configuration. The default SSSD configuration is not affected.
Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H). Weakness: CWE-476.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat OpenShift Container Platform 4. Will not fix / out of support: Red Hat Enterprise Linux 6.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: libsss_autofs; Red Hat package: libsss_certmap; Red Hat package: libsss_nss_idmap-devel; Red Hat package: python3-libipa_hbac; and 27 more.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- 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.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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