A flaw was found in 389-ds-base. (CVE-2026-86345)
Description
A vulnerability in 389-ds-base allows an on-path attacker to inject a crafted LDAP message during StartTLS negotiation. The server does not discard plaintext bytes buffered from the client, leading to messageID collisions. This can cause a client to treat a failed authentication attempt as successful.
CVSS v3.1
Score 9.0critical
Affected software
pkg:deb/ubuntu/389-ds-base?arch=source&distro=esm-apps/xenialpkg:deb/ubuntu/389-ds-base?arch=source&distro=esm-apps/bionicpkg:deb/ubuntu/389-ds-base?arch=source&distro=esm-apps/focalpkg:deb/ubuntu/389-ds-base?arch=source&distro=jammypkg:deb/ubuntu/389-ds-base?arch=source&distro=noblepkg:deb/ubuntu/389-ds-base?arch=source&distro=stonkingpkg:deb/ubuntu/389-ds-base?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-86345 is a vulnerability in 389-ds-base where the server fails to discard plaintext bytes buffered from a client connection during StartTLS negotiation. This flaw enables an on-path attacker to inject a crafted LDAP message that is processed after the TLS upgrade. Due to messageID collision, the response to the injected message is delivered to the client instead of the client's own pending operation response. This can cause the client application to incorrectly treat a failed bind (authentication) attempt as successful.
Potential Impact
An attacker positioned on the network path can manipulate LDAP StartTLS negotiation to inject malicious LDAP messages. This can lead to authentication bypass where a client believes a failed authentication succeeded. The vulnerability has a CVSS score of 9.0, indicating high severity with potential for complete confidentiality, integrity, and availability compromise of the LDAP service.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or patch links are provided in the available data. Until a patch is available, consider restricting network access to LDAP services and monitoring for suspicious activity related to StartTLS negotiation.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-86345
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.10","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ad3f5502cdf04f6566586ae
Added to database: 10/17/2026, 22:23:12 UTC
Last enriched: 10/17/2026, 23:24:59 UTC
Last updated: 10/17/2026, 23:24:59 UTC
Views: 4
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