An integer underflow was discovered in OpenLDAP before 2.4.57 leading to slapd crashes in the Certificate Exact Assertion processing, resulting in denial of service (schema_init.c serialNumberAndIssuerCheck).
A flaw was discovered in OpenLDAP before 2.4.57 leading to an assertion failure in slapd in the saslAuthzTo validation, resulting in denial of service.
A flaw was discovered in OpenLDAP before 2.4.57 leading to a slapd crash in the Values Return Filter control handling, resulting in denial of service (double free and out-of-bounds read).
A flaw was discovered in OpenLDAP before 2.4.57 leading to an invalid pointer free and slapd crash in the saslAuthzTo processing, resulting in denial of service.
A NULL pointer dereference was found in OpenLDAP server and was fixed in openldap 2.4.55, during a request for renaming RDNs. An unauthenticated attacker could remotely crash the slapd process by sending a specially crafted request, causing a Denial of Service.
libldap in certain third-party OpenLDAP packages has a certificate-validation flaw when the third-party package is asserting RFC6125 support. It considers CN even when there is a non-matching subjectAltName (SAN). This is fixed in, for example, openldap-2.4.46-10.el8 in Red Hat Enterprise Linux.
An issue was discovered in the server in OpenLDAP before 2.4.48. When the server administrator delegates rootDN (database admin) privileges for certain databases but wants to maintain isolation (e.g., for multi-tenant deployments), slapd does not properly stop a rootDN from requesting authorization as an identity from another database during a SASL bind or with a proxyAuthz (RFC 4370) control. (It is not a common configuration to deploy a system where the server administrator and a DB administrator enjoy different levels of trust.)
An issue was discovered in OpenLDAP 2.x before 2.4.48. When using SASL authentication and session encryption, and relying on the SASL security layers in slapd access controls, it is possible to obtain access that would otherwise be denied via a simple bind for any identity covered in those ACLs. After the first SASL bind is completed, the sasl_ssf value is retained for all new non-SASL connections. Depending on the ACL configuration, this can affect different types of operations (searches, modifications, etc.). In other words, a successful authorization step completed by one user affects the authorization requirement for a different user.
contrib/slapd-modules/nops/nops.c in OpenLDAP through 2.4.45, when both the nops module and the memberof overlay are enabled, attempts to free a buffer that was allocated on the stack, which allows remote attackers to cause a denial of service (slapd crash) via a member MODDN operation.