CVE-2026-103878 Apache Directory LDAP API: Injection of plaintext responses during StartTLS
Attackers can intercept sensitive data transmitted in plaintext during StartTLS operations in the Apache Directory LDAP API.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-103878?
CVE-2026-103878 is a high-severity vulnerability in Apache Directory LDAP API, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-345
Which versions are affected by CVE-2026-103878?
How do I fix CVE-2026-103878?
No fix has been published for CVE-2026-103878 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-103878 being exploited?
There is no known exploitation of CVE-2026-103878 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-103878, GHSA-vmxq-hqjm-cxv7, UBUNTU-CVE-2026-103878.