CVE-2026-90462

A flaw was found in SSSD. When configured with the LDAP access provider and ldap_access_order including ppolicy or lockout, a fail-open condition in the LDAP ppolicy access check can occur if a user lookup returns zero results. This can incorrectly return success and cache an allow decision, permitting continued authorization for a deleted or deprovisioned user. A remote attacker with prior valid account context could exploit this to maintain access to information and potentially make limited modifications to resources that should no longer be available.

• CVE-2026-90462: deny access in sdap_access_ppolicy_step_done() when the LDAP ppolicy user search returns zero entries, instead of returning success and caching an allow decision
• CVE-2026-90996: reject an empty request body in the NSS responder request parsers before body[blen - 1] is read

• CVE-2026-90462: deny access and cache the deny decision when the LDAP ppolicy access check lookup returns zero results, fixing a fail-open that let deleted or deprovisioned users keep passing access checks
• CVE-2026-90996: reject header-only requests with an empty body in the NSS responder parsers, preventing a size_t underflow on body[blen - 1] access that could crash the responder
• CVE-2026-104045: skip reparenting the autofs enumeration context to the maps table when its key was orphaned during the async request, fixing a memory leak in the autofs responder

This update for sssd fixes the following issues:

• CVE-2026-12610: cancelled or completed PAM request while the asynchronous child process is still running can lead to a use-after-free (bsc#1269807).
• CVE-2026-68742: unvalidated address lengths in NSS responder packet parsing can cause a heap out-of-bounds read (bsc#1273922).
• CVE-2026-68743: oversized length parameters in authentication requests can cause heap out-of-bounds reads (bsc#1273925).
• CVE-2026-68744: unshrunk packet allocations during group resolution can allow uninitialized heap memory disclosure (bsc#1273924).
• CVE-2026-90462: Fail-open in LDAP ppolicy access check allows continued authorization (bsc#1282584).
• CVE-2026-90463: out-of-bounds read in the NSS service request parsers (bsc#1280360).
• CVE-2026-90994: out-of-bounds read in PAM v1 parser (bsc#1280361).
• CVE-2026-90995: NULL pointer dereference in PAM responder (bsc#1280362).
• CVE-2026-90996: zero-length request body underflow in the NSS responder (bsc#1280363).
• CVE-2026-92821: access control bypass due to premature LDAP access rule evaluation (bsc#1284326).
• CVE-2026-104029: denial of service due to out-of-bounds read in autofs responder (bsc#1284314).
• CVE-2026-104031: denial of service via memory exhaustion in autofs responder (bsc#1284316).
• CVE-2026-104033: access control bypass due to improper LDAP shadow expiration check (bsc#1284318).
• CVE-2026-104036: denial of service due to out-of-bounds write in NFS idmap plugin (bsc#1284321).
• CVE-2026-104037: denial of service due to packet length underflow in autofs responder (bsc#1284322).
• CVE-2026-104038: denial of service via missing SID extension in certificate mapping (bsc#1284323).
• CVE-2026-104039: denial of service due to stale connection state reuse in PAM GSSAPI responder (bsc#1284324).
• CVE-2026-104043: Denial of Service via undersized packet parsing in NSS responder (bsc#1284266).
• CVE-2026-104045: denial of service via race condition in autofs responder (bsc#1284470).