CVE-2026-103878: Apache Directory LDAP API: Injection of plaintext responses during StartTLS

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-02 · updated 2026-10-05
Weakness: CWE-345

Description

Cleartext transmission of sensitive information vulnerability in Apache Directory LDAP API. A StartTLS extended operation started after a Search request has been sent can lead to receive data in plain text before the TLS Handshake has been completed. This issue affects Apache Directory LDAP API: from 2.1.0 before 2.1.9. Users are recommended to upgrade to version 2.1.9, which fixes the issue.

Affected products

Apache Software Foundation Apache Directory LDAP API: from 2.1.0 before 2.1.9 — fixed in 2.1.9

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Directory LDAP API 2.1.9. Check the vendor advisory for mitigations.

References

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