CVE-2026-41292Network attack vector

Denial of service via unbounded EDNS option parsing

Published May 20, 2026 · Updated Aug 26, 2026

Denial of service in NLnet Labs Unbound 1.25.0 and earlier allows remote attackers to exhaust resolver threads via EDNS-heavy DNS queries. The request parser accepts an unbounded list of EDNS options and allocates internal structures while walking the entire list. Any client able to query the resolver can consume worker capacity; coordinated queries degrade or deny DNS resolution without affecting data.

CVSS severity7.5
High
EPSS probability0.72%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in NLnet Labs Unbound 1.25.0 and earlier allows remote attackers to exhaust resolver threads via EDNS-heavy DNS queries. The request parser accepts an unbounded list of EDNS options and allocates internal structures while walking the entire list. Any client able to query the resolver can consume worker capacity; coordinated queries degrade or deny DNS resolution without affecting data.

The record

CVE
CVE-2026-41292
Published
May 20, 2026
Updated
Aug 26, 2026
Vendor
389 Directory Server
Product
Red Hat Enterprise Linux 6
Classifications
CWE-1050, CWE-770, CWE-407, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

389 Directory Server · Red Hat Enterprise Linux 6Affected versions are unavailable in this record.
NLnet Labs · Unboundversion=0 <1.25.1
389 Directory Server · Red Hat Enterprise Linux 10Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 7Affected versions are unavailable in this record.
389 Directory Server · Red Hat Hardened ImagesAffected versions are unavailable in this record.
389 Directory Server · Red Hat OpenShift Container Platform 4.22Affected versions are unavailable in this record.
389 Directory Server · Red Hat OpenStack PlatformAffected versions are unavailable in this record.
389 Directory Server · Red Hat OpenStack Services on OpenShiftAffected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.

Published CVSS scores

6.6NLnet LabsCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U
7.5Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1050Excessive Platform Resource Consumption within a Loop
CWE-770Allocation of Resources Without Limits or Throttling
CWE-407Inefficient Algorithmic Complexity
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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