CVE-2026-66374

HIGH

NIC Knot Resolver < 6.4.1 - Improper Validation of Specified Quantity in Input

Title source: rule
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-66374. PoCs published by venglin.

AI-analyzed exploit summary This repository contains a functional exploit for CVE-2026-66374, a heap buffer overflow in Knot Resolver 6.3.0's DNS-over-QUIC (DoQ) implementation. The exploit achieves remote code execution by corrupting a libgnutls cleanup handler via a controlled out-of-bounds write, enabling attacker-controlled RIP and RDI.

Description

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

Exploits (1)

nomisec WORKING POC
by venglin · poc
https://github.com/venglin/knot-doq

This repository contains a functional exploit for CVE-2026-66374, a heap buffer overflow in Knot Resolver 6.3.0's DNS-over-QUIC (DoQ) implementation. The exploit achieves remote code execution by corrupting a libgnutls cleanup handler via a controlled out-of-bounds write, enabling attacker-controlled RIP and RDI.

Classification
Working Poc 99%
Attack Type
Rce
Complexity
Complex
Reliability
Reliable
Target: Knot Resolver 6.3.0 (kresd daemon)
No auth needed
Prerequisites: ASLR disabled on target (kernel.randomize_va_space = 0) for deterministic addresses · Target must be running Knot Resolver 6.3.0 with DoQ enabled · Network access to the DoQ port (default: 8853)
mistral-large-3 · analyzed Jul 25, 2026 Full analysis →

References (2)

Core 2

Scores

CVSS v3 8.1
EPSS 0.0039
EPSS Percentile 31.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:L

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact partial

Details

CWE
CWE-1284
Status published
Products (1)
nic/Knot Resolver < 6.4.1
Published Jul 25, 2026
Tracked Since Jul 25, 2026