CVE-2026-10846: CWE-346 Origin Validation Error in NLnet Labs ldns
NLnet Labs ldns versions 1. 2. 0 through 1. 9. 0 have a vulnerability in their UDP stub resolver functionality where responses are not properly validated against the query's destination address, port, query ID, or question. This flaw allows off-path attackers to perform DNS cache poisoning attacks. The drill tool included with ldns is also affected. The vulnerability has a high severity score of 8. 2. No official patch or remediation guidance is currently available.
AI Analysis
Technical Summary
NLnet Labs ldns versions 1.2.0 up to and including 1.9.0, when used as a stub resolver over UDP, do not validate that the response source address and port match the query destination address and port. Additionally, the response is not matched against the query ID or the question section. This origin validation error (CWE-346) enables off-path attackers to inject forged DNS responses, leading to potential cache poisoning. The vulnerability affects applications using ldns for stub resolver functionality and the drill tool shipped with ldns. There is no vendor advisory or patch available at this time.
Potential Impact
The vulnerability allows off-path attackers to perform DNS cache poisoning attacks by injecting forged DNS responses that are accepted due to lack of proper origin validation. This can lead to redirection of DNS queries to malicious destinations, impacting the integrity of DNS resolution for affected applications using ldns as a stub resolver over UDP.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should consider alternative DNS resolver implementations or additional network-level protections to mitigate off-path poisoning risks.
CVE-2026-10846: CWE-346 Origin Validation Error in NLnet Labs ldns
Description
NLnet Labs ldns versions 1. 2. 0 through 1. 9. 0 have a vulnerability in their UDP stub resolver functionality where responses are not properly validated against the query's destination address, port, query ID, or question. This flaw allows off-path attackers to perform DNS cache poisoning attacks. The drill tool included with ldns is also affected. The vulnerability has a high severity score of 8. 2. No official patch or remediation guidance is currently available.
CVSS v4.0
Score 8.2high
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
NLnet Labs ldns versions 1.2.0 up to and including 1.9.0, when used as a stub resolver over UDP, do not validate that the response source address and port match the query destination address and port. Additionally, the response is not matched against the query ID or the question section. This origin validation error (CWE-346) enables off-path attackers to inject forged DNS responses, leading to potential cache poisoning. The vulnerability affects applications using ldns for stub resolver functionality and the drill tool shipped with ldns. There is no vendor advisory or patch available at this time.
Potential Impact
The vulnerability allows off-path attackers to perform DNS cache poisoning attacks by injecting forged DNS responses that are accepted due to lack of proper origin validation. This can lead to redirection of DNS queries to malicious destinations, impacting the integrity of DNS resolution for affected applications using ldns as a stub resolver over UDP.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, users should consider alternative DNS resolver implementations or additional network-level protections to mitigate off-path poisoning risks.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- NLnet Labs
- Date Reserved
- 2026-06-04T12:06:54.996Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a2907048dd33fbd85fa8695
Added to database: 6/10/2026, 6:41:08 AM
Last enriched: 6/10/2026, 6:55:43 AM
Last updated: 6/10/2026, 7:42:49 AM
Views: 2
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