CVE-2026-18664

CRITICALNVD 9.19.1—
EchelonGraph scoreHIGH confidence

Score 9.1 from GitHub Security Advisory (severity: HIGH) published 2026-09-01. NVD baseline CVSS 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.1Exploit: None knownExposed: 0

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

When ranges are used for access control (i.e. of the form 1.2.3.4-1.2.3.25), because NSD wrongly compares the IP address with the range on little endian systems, IPs that were meant to be allowed may be denied, and, IPs that were meant to be denied access could be allowed. An IPv4 address is compared with IPv4 ranges as unsigned 32 bit numbers directly with the endianness of the host, but the values to compare are in network byte order (big-endian). With IPv6 addresses the comparison is done in 4 times a unsigned 32 bit number comparison, again with the endianness of the host where all values are actually in network bye order.

CVSS v3
9.1
EG Score
9.1(high)
EG Risk
41(Track)
EG Risk 41/100SSVC: 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
Severity91% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
26%
KEV
Not listed

Published

August 26, 2026

Last Modified

September 8, 2026

Advisory Details (1)

Auto-updated Sep 15, 2026
No patch confirmed yet.
generic
https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-18664.txt

Vendor Advisories for CVE-2026-18664(1)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
nsd4.10.1-1 ... 4.9.1-1 (24 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
nsd4.12.0-1 ... 4.15.1-1 (15 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
nsd4.12.0-1 ... 4.15.0~rc1-1 (14 versions)4.15.1-1—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 54× in last 7d / 124× 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 124 total refreshes for this CVE.

  1. 2026-09-19 10:04 UTCGHSA enrichment
  2. 2026-09-19 05:30 UTCGHSA enrichment
  3. 2026-09-19 01:32 UTCGHSA enrichment
  4. 2026-09-18 21:32 UTCEG score recompute
  5. 2026-09-18 21:32 UTCGHSA enrichment
  6. 2026-09-18 19:27 UTCEPSS rescore
  7. 2026-09-18 16:40 UTCGHSA enrichment
  8. 2026-09-18 12:43 UTCGHSA enrichment
  9. 2026-09-18 08:47 UTCGHSA enrichment
  10. 2026-09-18 04:51 UTCGHSA enrichment
  11. 2026-09-18 00:55 UTCGHSA enrichment
  12. 2026-09-17 20:59 UTCEG score recompute
  13. 2026-09-17 20:59 UTCGHSA enrichment
  14. 2026-09-17 15:32 UTCGHSA enrichment
  15. 2026-09-17 11:29 UTCGHSA enrichment
  16. 2026-09-17 07:27 UTCGHSA enrichment
  17. 2026-09-17 03:31 UTCGHSA enrichment
  18. 2026-09-16 23:35 UTCGHSA enrichment
  19. 2026-09-16 19:38 UTCGHSA enrichment
  20. 2026-09-16 15:41 UTCEG score recompute
  21. 2026-09-16 15:41 UTCGHSA enrichment
  22. 2026-09-16 14:07 UTCEPSS rescore
  23. 2026-09-16 11:28 UTCGHSA enrichment
  24. 2026-09-16 07:25 UTCEG score recompute
  25. 2026-09-16 07:25 UTCGHSA enrichment
Show 75 more
  1. 2026-09-16 05:14 UTCEPSS rescore
  2. 2026-09-16 03:29 UTCGHSA enrichment
  3. 2026-09-15 23:33 UTCGHSA enrichment
  4. 2026-09-15 19:26 UTCGHSA enrichment
  5. 2026-09-15 15:30 UTCGHSA enrichment
  6. 2026-09-15 11:32 UTCGHSA enrichment
  7. 2026-09-15 07:33 UTCGHSA enrichment
  8. 2026-09-15 03:37 UTCEG score recompute
  9. 2026-09-15 03:37 UTCGHSA enrichment
  10. 2026-09-14 23:41 UTCGHSA enrichment
  11. 2026-09-14 19:11 UTCGHSA enrichment
  12. 2026-09-14 15:15 UTCGHSA enrichment
  13. 2026-09-14 11:19 UTCGHSA enrichment
  14. 2026-09-14 07:23 UTCGHSA enrichment
  15. 2026-09-14 03:27 UTCGHSA enrichment
  16. 2026-09-13 23:31 UTCGHSA enrichment
  17. 2026-09-13 19:35 UTCEG score recompute
  18. 2026-09-13 19:35 UTCGHSA enrichment
  19. 2026-09-13 16:46 UTCEPSS rescore
  20. 2026-09-13 15:38 UTCGHSA enrichment
  21. 2026-09-13 11:38 UTCGHSA enrichment
  22. 2026-09-13 07:41 UTCGHSA enrichment
  23. 2026-09-13 03:46 UTCGHSA enrichment
  24. 2026-09-12 23:50 UTCGHSA enrichment
  25. 2026-09-12 19:54 UTCGHSA enrichment
  26. 2026-09-12 15:58 UTCEG score recompute
  27. 2026-09-12 15:58 UTCGHSA enrichment
  28. 2026-09-12 15:00 UTCEPSS rescore
  29. 2026-09-12 12:01 UTCGHSA enrichment
  30. 2026-09-12 08:05 UTCGHSA enrichment
  31. 2026-09-12 04:09 UTCGHSA enrichment
  32. 2026-09-12 00:12 UTCGHSA enrichment
  33. 2026-09-11 20:12 UTCGHSA enrichment
  34. 2026-09-11 16:09 UTCEG score recompute
  35. 2026-09-11 16:09 UTCGHSA enrichment
  36. 2026-09-11 14:52 UTCEPSS rescore
  37. 2026-09-11 12:08 UTCEG score recompute
  38. 2026-09-11 12:08 UTCGHSA enrichment
  39. 2026-09-11 09:36 UTCEPSS rescore
  40. 2026-09-11 08:12 UTCGHSA enrichment
  41. 2026-09-11 04:16 UTCGHSA enrichment
  42. 2026-09-11 00:20 UTCGHSA enrichment
  43. 2026-09-10 20:24 UTCGHSA enrichment
  44. 2026-09-10 16:28 UTCGHSA enrichment
  45. 2026-09-10 12:05 UTCEG score recompute
  46. 2026-09-10 12:05 UTCGHSA enrichment
  47. 2026-09-10 09:34 UTCEPSS rescore
  48. 2026-09-10 08:07 UTCGHSA enrichment
  49. 2026-09-10 04:10 UTCGHSA enrichment
  50. 2026-09-10 00:07 UTCGHSA enrichment
  51. 2026-09-09 16:59 UTCGHSA enrichment
  52. 2026-09-09 12:47 UTCGHSA enrichment
  53. 2026-09-09 08:44 UTCGHSA enrichment
  54. 2026-09-09 04:48 UTCGHSA enrichment
  55. 2026-09-09 00:52 UTCEG score recompute
  56. 2026-09-09 00:52 UTCGHSA enrichment
  57. 2026-09-08 22:00 UTCEPSS rescore
  58. 2026-09-08 20:20 UTCEG score recompute▲ 0.90
  59. 2026-09-08 20:20 UTCGHSA enrichment
  60. 2026-09-08 20:10 UTCNVD updateCVSS v3 → 9.1 · severity → CRITICAL
  61. 2026-09-08 03:42 UTCEG score recompute
  62. 2026-09-08 03:42 UTCGHSA enrichment
  63. 2026-09-07 16:01 UTCEPSS rescore
  64. 2026-09-07 15:12 UTCGHSA enrichment
  65. 2026-09-07 02:26 UTCGHSA enrichment
  66. 2026-09-06 13:53 UTCEG score recompute
  67. 2026-09-06 13:53 UTCGHSA enrichment
  68. 2026-09-06 13:47 UTCEPSS rescore
  69. 2026-09-06 01:22 UTCEG score recompute
  70. 2026-09-06 01:21 UTCGHSA enrichment
  71. 2026-09-05 12:50 UTCGHSA enrichment
  72. 2026-09-05 00:20 UTCEG score recompute
  73. 2026-09-05 00:20 UTCGHSA enrichment
  74. 2026-09-04 11:49 UTCEG score recompute
  75. 2026-09-04 11:49 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-18664?
CVE-2026-18664 is a critical vulnerability published on August 26, 2026. When ranges are used for access control (i.e. of the form 1.2.3.4-1.2.3.25), because NSD wrongly compares the IP address with the range on little endian systems, IPs that were meant to be allowed may be denied, and, IPs that were meant to be denied access could be allowed. An IPv4 address is…
When was CVE-2026-18664 disclosed?
CVE-2026-18664 was first published in the National Vulnerability Database on August 26, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18664 actively exploited?
CVE-2026-18664 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 73.6% of all scored CVEs.
What is the CVSS score of CVE-2026-18664?
CVE-2026-18664 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-18664?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18664, 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

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