CVE-2026-22185 is a vulnerability in the OpenLDAP Foundation's OpenLDAP product, specifically affecting the Lightning Memory-Mapped Database (LMDB) component used by the mdb_load utility. The vulnerability is a heap buffer underflow caused by an unsigned offset calculation in the readline() function. When processing malformed input, this calculation can underflow a heap pointer, resulting in an out-of-bounds read of one byte before the allocated heap buffer. This type of out-of-bounds read is classified under CWE-125 (Out-of-bounds Read) and CWE-191 (Integer Underflow). The impact of this flaw includes the potential for a local attacker to cause a denial of service by crashing the application or process using LMDB, and possibly to disclose limited heap memory contents, which could include sensitive information. The CVSS v4.0 score is 7.0 (high severity), reflecting that the attack vector is local (AV:L), with low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), limited confidentiality impact (VC:L), no integrity or availability impact (VI:N, VA:H), and no scope change. The vulnerability does not require authentication or user interaction, but exploitation requires local access to the system. No patches or fixes have been published at the time of reporting, and no known exploits are currently in the wild. The vulnerability affects all versions of OpenLDAP using LMDB as the backend database, which is common in many LDAP deployments due to LMDB's performance and reliability benefits.

For European organizations, this vulnerability poses a risk primarily to systems running OpenLDAP with LMDB backend, which are often used in identity management, authentication, and directory services. A successful exploitation could lead to denial of service, disrupting critical authentication services and potentially causing operational downtime. Additionally, the limited disclosure of heap memory contents could expose sensitive information, such as credentials or configuration data, increasing the risk of further attacks. Organizations in sectors such as government, finance, telecommunications, and healthcare, which rely heavily on LDAP for access control and directory services, could face significant operational and reputational damage. The local attack vector limits remote exploitation, but insider threats or compromised local accounts could leverage this vulnerability. The absence of patches increases the urgency for mitigation to prevent exploitation. Given the widespread use of OpenLDAP in Europe, especially in enterprise and public sector environments, the impact could be substantial if not addressed promptly.

1. Restrict local access to systems running OpenLDAP with LMDB backend to trusted administrators only, minimizing the risk of local exploitation. 2. Implement strict input validation and sanitization on any interfaces or scripts that interact with mdb_load or LMDB data files to prevent malformed input processing. 3. Monitor logs and system behavior for signs of crashes or abnormal memory access patterns indicative of exploitation attempts. 4. Employ application whitelisting and endpoint protection solutions to detect and block unauthorized execution of mdb_load or related utilities. 5. Consider isolating critical LDAP servers in hardened environments with limited user access and enhanced auditing. 6. Stay informed on vendor updates and apply patches immediately once they become available. 7. Conduct internal audits to identify all instances of OpenLDAP using LMDB and assess exposure. 8. Use memory protection mechanisms and runtime security tools that can detect and prevent heap underflow or out-of-bounds reads. 9. Develop incident response plans specifically addressing potential denial of service and data leakage scenarios related to this vulnerability. 10. Engage with OpenLDAP community or vendors for early access to patches or workarounds.