Vulnerability in Nic Knot Resolver

CVE-2026-66374

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

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:H/A:L.

EPSS exploit prediction

EPSS: 0.006 (49.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 49.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-66374: held from 0.006 to 0.006.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-66374?
CVE-2026-66374 is a high-severity vulnerability in Nic Knot Resolver, classified under Improper Validation of Specified Quantity in Input. CVSS score: 8.1/10. Published 2026-07-25.
How severe is CVE-2026-66374?
High severity. CVSS v3 base score is 8.1 out of 10.
Is CVE-2026-66374 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.