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
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.
Fixes and workarounds
Workaround
Disable StartTLS on port 389 and require ldaps:// (port 636) instead, which has no cleartext prefix to inject into. No configuration-only mitigation fully closes the issue on port 389 while StartTLS remains enabled.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Directory Server 11 Red Hat 389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Directory Server 11 Red Hat redhat-ds:11/389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Directory Server 12 Red Hat 389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Directory Server 12 Red Hat redhat-ds:12/389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Directory Server 13 Red Hat 389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 10 Red Hat 389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 6 Red Hat 389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
| Red Hat Enterprise Linux 7 Red Hat 389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unknown |
CNA: redhat |
| Red Hat Enterprise Linux 8 Red Hat 389-ds:1.4/389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 8 Red Hat 389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 9 Red Hat 389-ds-base
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 9.0 critical |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H | CNA: redhat |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://access.redhat.com/security/cve/CVE-2026-86345CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2529332CNA: redhat · issue-tracking, x_refsource_REDHAT
For agents and automation
Read public disclosures for free as Markdown or JSON. Compatible browsers also expose native WebMCP tools to search disclosures, read this page, and discover API access.
Use the ontology-linked Cyber API with x402 pay per request, or a Y2 Pro or Elite API key with the intel:cyber scope.
Endpoints and access details
https://api.y2.dev/api/v2/cyber/cveshttps://api.y2.dev/api/v2/cyber/cves/{cveId}
A workspace owner or admin can create a Pro or Elite API key. Send Authorization: Bearer <Y2_API_KEY> from your trusted agent runtime.
For x402, omit Authorization and read the HTTP 402 payment challenge before signing a retry. Public browser tools do not make payments.