Authentication-result spoofing via retained pre-TLS LDAP bytes
Published Oct 1, 2026 · Updated Oct 1, 2026
Authentication-result spoofing in Red Hat Directory Server allows man-in-the-middle attackers to falsify an LDAP bind response during StartTLS. The 389-ds-base server retains plaintext bytes buffered before the TLS upgrade and processes an injected LDAP message afterward, allowing its response to collide with the client's pending message ID. An on-path position and a client using StartTLS are required; the client can then treat a failed bind as successful.
Summary
What happened
Authentication-result spoofing in Red Hat Directory Server allows man-in-the-middle attackers to falsify an LDAP bind response during StartTLS. The 389-ds-base server retains plaintext bytes buffered before the TLS upgrade and processes an injected LDAP message afterward, allowing its response to collide with the client's pending message ID. An on-path position and a client using StartTLS are required; the client can then treat a failed bind as successful.
The record
- CVE
- CVE-2026-86345
- Published
- Oct 1, 2026
- Updated
- Oct 1, 2026
- Vendor
- libuser Project
- Product
- Red Hat Directory Server
- Classifications
- T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Oct 1, 2026CVE publishedPublication date reported by the CVE source.
- Oct 1, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
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