CVE-2026-66374

HIGHPre-NVD 8.18.1—
EchelonGraph scoreHIGH confidence

Score 8.1 from GitHub Security Advisory (severity: HIGH) published 2026-07-25. a secondary CVSS source baseline 8.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this weekElevated
8.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.1Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

CVSS v3
8.1
EG Score
8.1(high)
EG Risk
52(Track)
EG Risk 52/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity81% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
32%
KEV
Not listed

Published

July 25, 2026

Last Modified

July 27, 2026

Advisory Details (2)

Auto-updated Jul 25, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

oss-security - Knot Resolver 6.3.0 DNS-over-QUIC heap buffer overflow (RCE)

https://openwall.com/lists/oss-security/2026/07/23/6
generic🟡 PoC Available

GitHub - venglin/knot-doq: PoC for a Knot Resolver 6.3.0 DNS-over-QUIC heap overflow (RCE as knot-resolver), fixed in 6.4.1. Coordinated disclosure. · GitHub

https://github.com/venglin/knot-doq

Vendor Advisories for CVE-2026-66374(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 16× in last 7d / 16× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-27 16:26 UTCEG score recompute
  2. 2026-07-27 16:26 UTCGHSA enrichment
  3. 2026-07-27 15:31 UTCEG score recompute
  4. 2026-07-27 15:31 UTCGHSA enrichment
  5. 2026-07-27 14:14 UTCEPSS rescore
  6. 2026-07-27 03:49 UTCGHSA enrichment
  7. 2026-07-26 15:22 UTCEG score recompute
  8. 2026-07-26 15:22 UTCGHSA enrichment
  9. 2026-07-26 14:54 UTCEPSS rescore
  10. 2026-07-26 14:54 UTCEPSS rescore
  11. 2026-07-26 02:55 UTCEG score recompute
  12. 2026-07-26 02:54 UTCGHSA enrichment
  13. 2026-07-25 14:18 UTCEPSS rescore
  14. 2026-07-25 14:18 UTCEPSS rescore
  15. 2026-07-25 00:57 UTCEG score recompute
  16. 2026-07-25 00:56 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-66374?
CVE-2026-66374 is a high vulnerability published on July 25, 2026. Knot Resolver before 6.4.1 allows remote code execution via a heap-based buffer overflow in the DoQ (DNS-over-QUIC) receive path.
When was CVE-2026-66374 disclosed?
CVE-2026-66374 was first published in the National Vulnerability Database on July 25, 2026, with the most recent update on July 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66374 actively exploited?
CVE-2026-66374 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 68.5% of all scored CVEs.
What is the CVSS score of CVE-2026-66374?
CVE-2026-66374 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-66374?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66374, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-66374

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