Medium [CVE-2026-90996] Sssd: sssd: denial of service in nss responder via crafted zero-length requests
This medium-severity Red Hat Linux advisory covers CVE-2026-90996 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. A local unprivileged user could send a specially crafted request with a zero-length body to the Network Security Services (NSS) responder.
This could lead to a denial-of-service condition, causing the NSS responder to become unstable or terminate. This vulnerability affects the availability of the system responder.
This flaw is rated Moderate. A local unprivileged attacker can trigger a denial of service in the SSSD NSS responder by sending a crafted request to its local UNIX socket.
This impact is limited to availability and requires local access, preventing broader system compromise or remote exploitation. Red Hat severity: Moderate — CVSS 4 (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).
Weakness: CWE-191. 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, restrict access to the NSS responder UNIX socket or disable the NSS responder if it is not required. The NSS responder can be disabled by editing the `/etc/sssd/sssd.conf` file and removing `nss` from the `services` line in the `[sssd]` section. After modifying the configuration, restart the SSSD service for the changes to take effect. Disabling the NSS responder may impact local user and group resolution. Example: ```bash # Remove 'nss' from the services line in /etc/sssd/sssd.conf # Before: services = nss, pam, autofs # After: services = pam, autofs sudo systemctl restart sssd ``` Warning: Restarting the `sssd` service will temporarily interrupt authentication and authorization services.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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