CVE-2026-86345

CRITICAL 9.0

389-ds-base: 389-ds-base: starttls plaintext-buffer retention allows on-path attacker to forge an ldap client's authentication result

CVSS Score

9.0

EPSS Score

0.0%

EPSS Percentile

0th

A flaw was found in 389-ds-base. The server does not discard plaintext bytes already buffered from a client connection when negotiating StartTLS, allowing an on-path attacker to inject a crafted LDAP message that is processed after the TLS upgrade and whose response is delivered to the client in place of the client's own pending operation's response, due to messageID collision. This can cause a client application to treat a failed authentication (bind) attempt as successful.

CWE	CWE-923
Vendor	red hat
Product	red hat directory server 11
Published	Oct 1, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

Red Hat / Red Hat Directory Server 11

All versions affected

Red Hat / Red Hat Directory Server 11

All versions affected

Red Hat / Red Hat Directory Server 12

All versions affected

Red Hat / Red Hat Directory Server 12

All versions affected

Red Hat / Red Hat Directory Server 13

All versions affected

Red Hat / Red Hat Enterprise Linux 10

All versions affected

Red Hat / Red Hat Enterprise Linux 6

All versions affected

Red Hat / Red Hat Enterprise Linux 7

All versions affected

Red Hat / Red Hat Enterprise Linux 8

All versions affected

Red Hat / Red Hat Enterprise Linux 8

All versions affected

Red Hat / Red Hat Enterprise Linux 9

All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗

access.redhat.com: https://access.redhat.com/security/cve/CVE-2026-86345 bugzilla.redhat.com: https://bugzilla.redhat.com/show_bug.cgi?id=2529332

Credits

Red Hat would like to thank xclow3n for reporting this issue.