What is CVE-2026-86344?
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.
The record classifies CVE-2026-86344 under weakness class CWE-400. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on availability. 8 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 4 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.5 — HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS (FIRST)
- 0.3% probability of exploitation in the next 30 days, higher than 25.9% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 4.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-10-01, last modified 2026-10-02
Is CVE-2026-86344 being exploited?
It currently carries a trending score of 36 in the Threadlinqs vulnerability feed.
Affected products and versions
- Red Hat: Directory Server 11, Directory Server 12, Directory Server 13, Enterprise Linux 10, Enterprise Linux 6, Enterprise Linux 7, Enterprise Linux 8, Enterprise Linux 9
How to fix CVE-2026-86344
No vendor patch reference has been recorded for CVE-2026-86344 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-86344
No threat campaign in the Threadlinqs corpus currently references CVE-2026-86344, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on .