High · CVSS 7.5CVE-2026-86344

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

Answer in brief

CVE-2026-86344 records a High severity (CVSS 7.5) vulnerability in 389-ds-base: 389-ds-base: unauthenticated worker-thread-pool exhaustion via completed-operation-then-incomplete-pdu connection requeue. The current sources do not mark it as known exploited. The current feed maps Red Hat/389-ds:1.4/389-ds-base (generic), Red Hat/389-ds-base (generic), Red Hat/redhat-ds:11/389-ds-base (generic), Red Hat/redhat-ds:12/389-ds-base (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 1, 2026Updated Oct 1, 2026Source checked Oct 2, 2026First seen by HOL Oct 1, 2026Material review Oct 1, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.5
Exploitation: Not marked as known exploited
Affected software: 4 mapped packages or products
Fix availability: Not reported

Why this deserves its current priority

CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Red Hat/389-ds:1.4/389-ds-base (generic), Red Hat/389-ds-base (generic), Red Hat/redhat-ds:11/389-ds-base (generic), Red Hat/redhat-ds:12/389-ds-base (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Red Hat/389-ds:1.4/389-ds-basegeneric	*	Not reported
Red Hat/389-ds-basegeneric	*	Not reported
Red Hat/redhat-ds:11/389-ds-basegeneric	*	Not reported
Red Hat/redhat-ds:12/389-ds-basegeneric	*	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Red Hat/389-ds:1.4/389-ds-base, Red Hat/389-ds-base, Red Hat/redhat-ds:11/389-ds-base.
Review the reported fix. Source-reported 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.

Evidence timeline and material changes

Published upstream
Oct 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 1, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 1, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.