CVE-2026-40622

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory published 2026-05-20. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this week
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

NLnet Labs Unbound 1.16.2 up to and including version 1.25.0 has a vulnerability of the 'ghost domain names' family of attacks that could extend the ghost domain window by up to one cached TTL configured value. Similar to other 'ghost domain names' attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single client NS query can cause Unbound to overwrite the cached expired parent-side referral NS rrset with the child-side apex NS rrset and essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In configurations where 'harden-referral-path: yes' is used (non-default configuration), no client NS query is required since Unbound implicitly performs that query. Unbound 1.25.1 contains a patch with a fix that does not allow extension of TTLs for (parent) NS records regardless of their trust.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
6.8%
KEV
Not listed

Published

May 20, 2026

Last Modified

May 26, 2026

Advisory Details (1)

Auto-updated May 20, 2026
No patch confirmed yet.
generic
https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-40622.txt

Vendor Advisories for CVE-2026-40622(2)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuunbound-host (1.13.1-1ubuntu5.15) @ jammy2026-06-29ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 10× in last 7d / 52× 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 169 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-40622?
CVE-2026-40622 is a high vulnerability published on May 20, 2026. NLnet Labs Unbound 1.16.2 up to and including version 1.25.0 has a vulnerability of the 'ghost domain names' family of attacks that could extend the ghost domain window by up to one cached TTL configured value. Similar to other 'ghost domain names' attacks, an adversary needs to control a (ghost)…
When was CVE-2026-40622 disclosed?
CVE-2026-40622 was first published in the National Vulnerability Database on May 20, 2026, with the most recent update on May 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40622 actively exploited?
CVE-2026-40622 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 6.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-40622?
CVE-2026-40622 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-40622?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40622, 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.

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