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Vulnerability · Published Oct 1, 2026 · Assigned by redhat

CVE-2026-86344389-ds-base: 389-ds-base: unauthenticated worker-thread-pool exhaustion via completed-operation-then-incomplete-pdu connection requeue

High 7.5

In plain English

A high-severity uncontrolled resource consumption in Red Hat Directory Server 11 from Red Hat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.3%top 71.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12389-ds-baseno fix listedDEBIAN-CVE-2026-86344
Debian:13389-ds-baseno fix listedDEBIAN-CVE-2026-86344
Ubuntu:22.04:LTS389-ds-baseno fix listedUBUNTU-CVE-2026-86344
Ubuntu:24.04:LTS389-ds-baseno fix listedUBUNTU-CVE-2026-86344
Ubuntu:26.04:LTS389-ds-baseno fix listedUBUNTU-CVE-2026-86344
Ubuntu:26.10389-ds-baseno fix listedUBUNTU-CVE-2026-86344

Affected products (as reported)

VendorProductVersions
Red Hat Red Hat Directory Server 11 see references
Red Hat Red Hat Directory Server 11 see references
Red Hat Red Hat Directory Server 12 see references
Red Hat Red Hat Directory Server 12 see references
Red Hat Red Hat Directory Server 13 see references
Red Hat Red Hat Enterprise Linux 10 see references
Red Hat Red Hat Enterprise Linux 6 see references
Red Hat Red Hat Enterprise Linux 7 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 8 see references
Red Hat Red Hat Enterprise Linux 9 see references

Weakness: CWE-400 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References