Upstream information

CVE-2026-42534 at MITRE

Description

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the jostle logic that could defeat its purpose and degrade resolution performance. Retransmits of the same query could renew the age of slow running queries and not allow the jostle logic to see them as aged and potential targets for replacement with new queries. An adversary who can query a vulnerable Unbound and who can control a domain name server that replies slowly and/or maliciously to Unbound's queries can exploit the vulnerability and degrade the resolution performance of Unbound. When Unbound's 'num-queries-per-thread' reaches its limit, the jostle logic kicks in. When a new query comes in, half of the available queries that are also slow to resolve are candidates for replacement. The vulnerability then happens because duplicate queries that need resolution would skew the aging result by using the timestamp of the latest duplicate query instead of the original one that started the resolution effort. Cache and local data response performance remains unaffected. Coordinated attacks could raise this to a denial of resolution service. Unbound 1.25.1 contains a patch with a fix to attach an initial, non-updatable start time for incoming queries that allow the jostle logic to work as intended.

SUSE information

Overall state of this security issue: Pending

This issue is currently rated as having moderate severity.

CVSS v3 Scores
CVSS detail SUSE
Base Score 5.9
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact None
Integrity Impact None
Availability Impact High
CVSSv3 Version 3.1
CVSS v4 Scores
CVSS detail CNA (NLnet Labs)
Base Score 6.9
Vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User Interaction None
Vulnerable System Confidentiality Impact None
Vulnerable System Integrity Impact None
Vulnerable System Availability Impact Low
Subsequent System Confidentiality Impact None
Subsequent System Integrity Impact None
Subsequent System Availability Impact None
CVSSv4 Version 4.0
SUSE Bugzilla entry: 1265585 [NEW]

No SUSE Security Announcements cross referenced.


Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products under general support and receiving all security fixes.
SUSE Linux Enterprise Desktop 15 SP7 unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP7 unbound Affected
SUSE Linux Enterprise Micro 5.5 unbound Affected
SUSE Linux Enterprise Module for Basesystem 15 SP7 unbound Affected
SUSE Linux Enterprise Module for Package Hub 15 SP7 unbound Affected
SUSE Linux Enterprise Server 15 SP7 unbound Affected
SUSE Linux Enterprise Server 16.0 unbound Affected
SUSE Linux Enterprise Server 16.1 unbound Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP7 unbound Affected
SUSE Linux Enterprise Server for SAP applications 16.0 unbound Affected
SUSE Linux Enterprise Server for SAP applications 16.1 unbound Affected
SUSE Linux Micro 6.0 unbound Affected
SUSE Linux Micro 6.1 unbound Affected
SUSE Linux Micro 6.2 unbound Affected
openSUSE Leap 16.0 unbound Affected
Products under Long Term Service Pack support and receiving important and critical security fixes.
SUSE Linux Enterprise High Performance Computing 15 SP4 unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP5 unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS unbound Affected
SUSE Linux Enterprise Module for Basesystem 15 SP4 unbound Affected
SUSE Linux Enterprise Module for Basesystem 15 SP5 unbound Affected
SUSE Linux Enterprise Module for Basesystem 15 SP6 unbound Affected
SUSE Linux Enterprise Server 15 SP4 unbound Affected
SUSE Linux Enterprise Server 15 SP4-LTSS unbound Affected
SUSE Linux Enterprise Server 15 SP5 unbound Affected
SUSE Linux Enterprise Server 15 SP5-LTSS unbound Affected
SUSE Linux Enterprise Server 15 SP6 unbound Affected
SUSE Linux Enterprise Server 15 SP6-LTSS unbound Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP6 unbound Affected
SUSE Manager Proxy 4.3 unbound Affected
SUSE Manager Proxy LTS 4.3 unbound Affected
SUSE Manager Retail Branch Server 4.3 unbound Affected
SUSE Manager Retail Branch Server LTS 4.3 unbound Affected
SUSE Manager Server 4.3 unbound Affected
SUSE Manager Server LTS 4.3 unbound Affected
Products past their end of life and not receiving proactive updates anymore.
SUSE CaaS Platform 4.0 unbound Affected
SUSE Enterprise Storage 6 unbound Affected
SUSE Enterprise Storage 7 unbound Affected
SUSE Enterprise Storage 7.1 unbound Affected
SUSE Linux Enterprise Desktop 15 SP1 unbound Affected
SUSE Linux Enterprise Desktop 15 SP2 unbound Affected
SUSE Linux Enterprise Desktop 15 SP3 unbound Affected
SUSE Linux Enterprise Desktop 15 SP4 unbound Affected
SUSE Linux Enterprise Desktop 15 SP5 unbound Affected
SUSE Linux Enterprise Desktop 15 SP6 unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP1 unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP2 unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP3 unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS unbound Affected
SUSE Linux Enterprise High Performance Computing 15 SP6 unbound Affected
SUSE Linux Enterprise Module for Basesystem 15 SP1 unbound Affected
SUSE Linux Enterprise Module for Basesystem 15 SP2 unbound Affected
SUSE Linux Enterprise Module for Basesystem 15 SP3 unbound Affected
SUSE Linux Enterprise Module for Package Hub 15 SP3 unbound Affected
SUSE Linux Enterprise Module for Package Hub 15 SP4 unbound Affected
SUSE Linux Enterprise Module for Package Hub 15 SP5 unbound Affected
SUSE Linux Enterprise Module for Package Hub 15 SP6 unbound Affected
SUSE Linux Enterprise Real Time 15 SP2 unbound Affected
SUSE Linux Enterprise Real Time 15 SP3 unbound Affected
SUSE Linux Enterprise Real Time 15 SP4 unbound Affected
SUSE Linux Enterprise Server 15 SP1 unbound Affected
SUSE Linux Enterprise Server 15 SP1-BCL unbound Affected
SUSE Linux Enterprise Server 15 SP1-LTSS unbound Affected
SUSE Linux Enterprise Server 15 SP2 unbound Affected
SUSE Linux Enterprise Server 15 SP2-BCL unbound Affected
SUSE Linux Enterprise Server 15 SP2-LTSS unbound Affected
SUSE Linux Enterprise Server 15 SP3 unbound Affected
SUSE Linux Enterprise Server 15 SP3-BCL unbound Affected
SUSE Linux Enterprise Server 15 SP3-LTSS unbound Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP1 unbound Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP2 unbound Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP3 unbound Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP4 unbound Affected
SUSE Linux Enterprise Server for SAP Applications 15 SP5 unbound Affected
SUSE Manager Proxy 4.0 unbound Affected
SUSE Manager Proxy 4.1 unbound Affected
SUSE Manager Proxy 4.2 unbound Affected
SUSE Manager Retail Branch Server 4.0 unbound Affected
SUSE Manager Retail Branch Server 4.1 unbound Affected
SUSE Manager Retail Branch Server 4.2 unbound Affected
SUSE Manager Server 4.0 unbound Affected
SUSE Manager Server 4.1 unbound Affected
SUSE Manager Server 4.2 unbound Affected
openSUSE Leap 15.3 unbound Affected
openSUSE Leap 15.4 unbound Affected
openSUSE Leap 15.5 unbound Affected
openSUSE Leap 15.6 unbound Affected


SUSE Timeline for this CVE

CVE page created: Tue May 19 10:30:36 2026
CVE page last modified: Wed May 20 15:36:23 2026