nic Knot Resolver up to 6.4.0 DNS-over-QUIC buffer overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.0$0-$5k2.40+

Summaryinfo

A vulnerability was found in nic Knot Resolver up to 6.4.0. It has been rated as critical. This affects an unknown part of the component DNS-over-QUIC. The manipulation leads to buffer overflow. This vulnerability is listed as CVE-2026-66374. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability, which was classified as critical, has been found in nic Knot Resolver up to 6.4.0. This issue affects an unknown function of the component DNS-over-QUIC. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Knot Resolver before 6.4.1 allows remote code execution via a heap-based buffer overflow in the DoQ (DNS-over-QUIC) receive path.

The advisory is shared at openwall.com. The identification of this vulnerability is CVE-2026-66374 since 07/25/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available.

Upgrading to version 6.4.1 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Knot Resolver 6.4.1

Timelineinfo

07/25/2026 Advisory disclosed
07/25/2026 +0 days CVE reserved
07/25/2026 +0 days VulDB entry created
07/25/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: openwall.com
Status: Confirmed

CVE: CVE-2026-66374 (🔒)
GCVE (CVE): GCVE-0-2026-66374
GCVE (VulDB): GCVE-100-383033

Entryinfo

Created: 07/25/2026 03:05
Changes: 07/25/2026 03:05 (56)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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