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
- Published
- Updated
- Reserved
- Assigned by
- redhat
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| redhatCNA (assigner) | 3.1 | Critical9.0 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
| NVDNVD · Awaiting Analysis | 3.1 | Critical9.0 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.38% · top 68% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.0.
Weakness
Affected products
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: unknown
Red Hat · Red Hat Enterprise Linux 7
All versions: unknown
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
What to do
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.
References (2)
- https://access.redhat.com/security/cve/CVE-2026-86345 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2529332 (opens in a new tab)issue-trackingx_refsource_REDHAT
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-86345)Record last updated .