Upstream information

CVE-2026-44390 at MITRE

Description

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability when handling replies with very large RRsets that Unbound needs to perform name compression for. Malicious upstream responses with very large RRsets with records that don't share a suffix above the root can cause Unbound to spend a considerable time applying name compression to downstream replies. This can lead to degraded performance and eventually denial of service in well orchestrated attacks. An adversary can exploit the vulnerability by querying Unbound for the specially crafted contents of a malicious zone with very large RRsets. Before Unbound replies to the query it will try to apply name compression which was an unbounded operation that could lock the CPU until the whole packet was complete. A compression limit was introduced in 1.21.1 for this but it didn't account for the case where records would not share any suffix above the root. That causes Unbound to go in a different code path because of the compression tree lookup failure and eventually not increment the compression counter for those operations. Unbound 1.25.1 contains a patch with a fix that increments the compression counter regardless of the compression tree lookup. This is a complement fix to CVE-2024-8508.

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: 1265584 [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 10:30:31 2026
CVE page last modified: Wed May 20 15:37:15 2026