What’s Vulnerable › Vulnerabilities

CVE-2026-86345: 389-ds-base: 389-ds-base: starttls plaintext-buffer retention allows on-path attacker to forge an ldap client's authentication result

• Severity: critical (CVSS 9.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-02 · updated 2026-10-07
• Weakness: CWE-923

Description

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.

Affected products

• Red Hat Directory Server 11: all versions
• Red Hat Directory Server 12: all versions
• Red Hat Directory Server 13: all versions
• Red Hat Enterprise Linux 10: all versions
• Red Hat Enterprise Linux 8: all versions
• Red Hat Enterprise Linux 9: all versions

References

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

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