A critical vulnerability in Spring Security’s embedded UnboundID LDAP server could allow remote attackers to authenticate with a well-known administrative bind identity and read or modify in-memory directory records.
Tracked as CVE-2026-59270, the issue was disclosed on August 20, 2026, and affects applications using UnboundIdContainer directly or through Spring Boot embedded LDAP auto-configuration.
The vulnerability is especially concerning for development, staging, and production-adjacent deployments where an embedded LDAP listener may have been unintentionally exposed outside localhost.
Critical Spring Security LDAP Flaw
An attacker only needs network reachability to the LDAP service; no prior authentication or user interaction is required.
Spring Security’s UnboundIdContainer unconditionally creates an administrative credential while configuring the embedded UnboundID LDAP listener to bind across all available network interfaces. This creates a dangerous combination: an externally reachable listener and a predictable administrative authentication path.
An attacker able to connect to the LDAP port can bind using the known administrative distinguished name (DN) and obtain privileged access to the application’s in-memory directory. The attacker could then enumerate, create, modify, or delete LDAP entries.
The impact depends on the data stored in the directory. Embedded LDAP instances may contain test accounts, group memberships, roles, organizational units, authentication attributes, and application-specific identity data.
Tampering with these records could alter authorization outcomes, disrupt test pipelines, expose identity information, or potentially enable a wider compromise where directory entries influence access-control decisions.
The CVSS v3.1 vector is AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L, reflecting a low-complexity, unauthenticated network attack with high confidentiality and integrity impact.
Affected versions
| Spring Security branch | Vulnerable versions | Fixed version |
|---|---|---|
| 7.1.x | 7.1.0 | 7.1.1 |
| 7.0.x | 7.0.0–7.0.6 | 7.0.7 |
| 6.5.x | 6.5.0–6.5.11 | 6.5.12* |
| 6.4.x | 6.4.0–6.4.18 | 6.4.19* |
| 5.8.x | 5.8.0–5.8.27 | 5.8.28* |
| 5.7.x | 5.7.0–5.7.25 | 5.7.26* |
Spring lists fixes for the older maintained branches as Enterprise Support Only, while 7.1.1 and 7.0.7 are available as OSS releases.
Mitigation
Security teams should identify applications that instantiate UnboundIdContainer or use configuration properties beginning with spring.ldap.embedded.*. They should also review container port mappings, host firewall rules, Kubernetes Services, cloud security groups, ingress paths, and load balancer configurations for LDAP exposure.
Upgrading to the applicable fixed release is the required remediation. Until upgrades are complete, organizations should restrict LDAP listener access to localhost or tightly controlled internal networks using external firewall rules and network policies.
Spring notes that remote exploitation requires the attacker’s ability to reach the listener port, making network isolation an important short-term containment measure.
Defenders should additionally monitor for unexpected LDAP binds and modifications to user, group, role, and authentication-related entries. Development and staging environments should be treated as potential exposure points, particularly where test identity stores resemble production authorization data.
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