CVE-2026-86344389-ds-base: 389-ds-base: unauthenticated worker-thread-pool exhaustion via completed-operation-then-incomplete-pdu connection requeue
- 7.5HighCVSS base score
- 0.35%Exploitation in 30 daysEPSS · top 71% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A flaw was found in 389-ds-base. An unauthenticated remote attacker can send a complete LDAP operation followed by the first bytes of an incomplete LDAPMessage on the same connection, causing the server to hand that connection to a second worker thread before the first worker's result is flushed. The second worker blocks until nsslapd-ioblocktimeout while holding the connection mutex, preventing delivery of the completed operation's result. Repeating this across a small number of connections proportional to the configured worker-thread pool size exhausts the entire pool under default configuration, denying service to all clients (anonymous and authenticated, plaintext and TLS) for as long as the attacker maintains the connections.
Timeline
ID reserved
By redhat
- 24 days later
· 24 days later
Published
- 34 days later
· 34 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| redhatCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Awaiting Analysis | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.35% · top 71% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
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: As an interim mitigation, administrators can limit the number of concurrent connections permitted per source IP address in front of the LDAP listener (for example via a firewall, load balancer, or a tool such as fail2ban), since exploitation requires several simultaneous connections from the same attacker. Upgrading to a fixed package remains the only complete resolution.
References
References2
- https://access.redhat.com/security/cve/CVE-2026-86344 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2529329 (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)
- EUVD EUVD-2026-91076 (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://cveledger.app/cve/CVE-2026-86344)Record last updated .