CVE-2026-86345

CRITICALCVSS 9/10

Last modified

CVE-2026-86345 is a critical-severity vulnerability rated 9/10 on the CVSS scale. 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.

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.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
Red HatRed Hat Directory Server 11All versions
Red HatRed Hat Directory Server 12All versions
Red HatRed Hat Directory Server 13All versions
Red HatRed Hat Enterprise Linux 10All versions
Red HatRed Hat Enterprise Linux 6All versions
Red HatRed Hat Enterprise Linux 7All versions
Red HatRed Hat Enterprise Linux 8All versions
Red HatRed Hat Enterprise Linux 9All versions

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-86345?
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.
How severe is CVE-2026-86345?
CVE-2026-86345 has a CVSS score of 9/10 (CRITICAL severity).
How do I fix CVE-2026-86345?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST