CVE-2026-66374

HIGHPre-NVD 8.18.1—
EchelonGraph scoreMEDIUM 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 — 3 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(medium)
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
41%
KEV
Not listed

Published

July 25, 2026

Last Modified

July 30, 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.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
knot-resolver5.3.1-1 ... 6.4.1-1 (42 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
knot-resolver5.6.0-1 ... 6.4.1-1 (28 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
knot-resolver5.7.5-1 ... 6.4.1-1 (18 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
knot-resolver5.7.5-1 ... 6.4.0-1 (17 versions)6.4.1-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 18× in last 7d / 85× 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.

Showing the most recent 100 of 178 total refreshes for this CVE.

  1. 2026-09-15 09:33 UTCEG score recompute
  2. 2026-09-15 09:33 UTCGHSA enrichment
  3. 2026-09-14 10:15 UTCGHSA enrichment
  4. 2026-09-13 21:45 UTCEG score recompute
  5. 2026-09-13 21:45 UTCGHSA enrichment
  6. 2026-09-13 06:13 UTCGHSA enrichment
  7. 2026-09-12 17:41 UTCEG score recompute
  8. 2026-09-12 17:41 UTCGHSA enrichment
  9. 2026-09-12 05:02 UTCGHSA enrichment
  10. 2026-09-11 16:34 UTCEG score recompute
  11. 2026-09-11 16:34 UTCGHSA enrichment
  12. 2026-09-11 14:53 UTCEPSS rescore
  13. 2026-09-11 09:37 UTCEPSS rescore
  14. 2026-09-11 02:29 UTCGHSA enrichment
  15. 2026-09-10 13:33 UTCEG score recompute
  16. 2026-09-10 13:33 UTCGHSA enrichment
  17. 2026-09-09 08:42 UTCEG score recompute
  18. 2026-09-09 08:42 UTCGHSA enrichment
  19. 2026-09-08 22:01 UTCEPSS rescore
  20. 2026-09-07 21:23 UTCEG score recompute
  21. 2026-09-07 21:23 UTCGHSA enrichment
  22. 2026-09-07 16:01 UTCEPSS rescore
  23. 2026-09-06 13:47 UTCEPSS rescore
  24. 2026-09-06 08:07 UTCGHSA enrichment
  25. 2026-09-05 19:22 UTCEG score recompute
Show 75 more
  1. 2026-09-05 19:22 UTCGHSA enrichment
  2. 2026-09-05 15:31 UTCEPSS rescore
  3. 2026-09-05 06:52 UTCEG score recompute
  4. 2026-09-05 06:52 UTCGHSA enrichment
  5. 2026-09-04 12:43 UTCEG score recompute
  6. 2026-09-04 12:43 UTCGHSA enrichment
  7. 2026-09-04 05:07 UTCEPSS rescore
  8. 2026-09-02 14:12 UTCEPSS rescore
  9. 2026-09-01 23:15 UTCEG score recompute
  10. 2026-09-01 23:15 UTCGHSA enrichment
  11. 2026-09-01 13:54 UTCEPSS rescore
  12. 2026-09-01 04:40 UTCEPSS rescore
  13. 2026-08-31 01:11 UTCEG score recompute
  14. 2026-08-31 01:11 UTCGHSA enrichment
  15. 2026-08-30 19:17 UTCEPSS rescore
  16. 2026-08-30 12:44 UTCEG score recompute
  17. 2026-08-30 12:44 UTCGHSA enrichment
  18. 2026-08-30 01:22 UTCEPSS rescore
  19. 2026-08-30 00:14 UTCEG score recompute
  20. 2026-08-30 00:14 UTCGHSA enrichment
  21. 2026-08-28 21:42 UTCEPSS rescore
  22. 2026-08-27 21:06 UTCEG score recompute
  23. 2026-08-27 21:06 UTCGHSA enrichment
  24. 2026-08-27 02:53 UTCEG score recompute
  25. 2026-08-27 02:53 UTCGHSA enrichment
  26. 2026-08-26 14:47 UTCEPSS rescore
  27. 2026-08-26 14:25 UTCGHSA enrichment
  28. 2026-08-26 01:55 UTCEG score recompute
  29. 2026-08-26 01:55 UTCGHSA enrichment
  30. 2026-08-25 13:49 UTCEPSS rescore
  31. 2026-08-25 13:28 UTCGHSA enrichment
  32. 2026-08-25 00:56 UTCEG score recompute
  33. 2026-08-25 00:56 UTCGHSA enrichment
  34. 2026-08-24 12:30 UTCEG score recompute
  35. 2026-08-24 12:30 UTCGHSA enrichment
  36. 2026-08-24 00:03 UTCGHSA enrichment
  37. 2026-08-23 11:36 UTCEG score recompute
  38. 2026-08-23 11:36 UTCGHSA enrichment
  39. 2026-08-23 00:19 UTCEPSS rescore
  40. 2026-08-22 23:09 UTCGHSA enrichment
  41. 2026-08-22 10:42 UTCEG score recompute
  42. 2026-08-22 10:42 UTCGHSA enrichment
  43. 2026-08-21 23:49 UTCEPSS rescore
  44. 2026-08-21 22:15 UTCGHSA enrichment
  45. 2026-08-21 09:37 UTCEG score recompute
  46. 2026-08-21 09:37 UTCGHSA enrichment
  47. 2026-08-20 22:56 UTCEPSS rescore
  48. 2026-08-20 21:10 UTCGHSA enrichment
  49. 2026-08-20 08:43 UTCGHSA enrichment
  50. 2026-08-19 20:16 UTCEG score recompute
  51. 2026-08-19 20:16 UTCGHSA enrichment
  52. 2026-08-19 17:04 UTCEPSS rescore
  53. 2026-08-19 07:17 UTCGHSA enrichment
  54. 2026-08-18 18:51 UTCEG score recompute
  55. 2026-08-18 18:51 UTCGHSA enrichment
  56. 2026-08-18 13:48 UTCEPSS rescore
  57. 2026-08-18 01:26 UTCEG score recompute
  58. 2026-08-18 01:26 UTCGHSA enrichment
  59. 2026-08-17 13:47 UTCEPSS rescore
  60. 2026-08-17 12:40 UTCGHSA enrichment
  61. 2026-08-17 00:13 UTCEG score recompute
  62. 2026-08-17 00:13 UTCGHSA enrichment
  63. 2026-08-16 14:56 UTCEPSS rescore
  64. 2026-08-16 11:45 UTCEG score recompute
  65. 2026-08-16 11:45 UTCGHSA enrichment
  66. 2026-08-15 23:19 UTCGHSA enrichment
  67. 2026-08-15 10:52 UTCEG score recompute
  68. 2026-08-15 10:52 UTCGHSA enrichment
  69. 2026-08-15 01:30 UTCEPSS rescore
  70. 2026-08-14 22:25 UTCGHSA enrichment
  71. 2026-08-14 09:58 UTCEG score recompute
  72. 2026-08-14 09:58 UTCGHSA enrichment
  73. 2026-08-13 22:00 UTCEPSS rescore
  74. 2026-08-13 21:31 UTCGHSA enrichment
  75. 2026-08-13 09:04 UTCGHSA enrichment

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 30, 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 58.7% 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-66374

Explore →

Is Your Infrastructure Affected by CVE-2026-66374?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs