CVE-2026-41637

LOWPre-NVD 3.73.7—
EchelonGraph scoreMEDIUM confidence

Score 3.7 from GitHub Security Advisory (severity: LOW) published 2026-07-22. a secondary CVSS source baseline 3.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
3.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 3.7Exploit: None knownExposed: 0

A fix is available — apply it.

In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, client terminated DNS-over-QUIC (DoQ) queries are not accounted properly by Unbound resulting in low-cost inflation of the waiting number of replies for already in-flight resolution queries. This results in degradation of resolution service for new clients for already in-flight queries. A malicious actor can exploit the vulnerability by issuing DoQ queries for query names that need resolution and proceeding on immediately terminating the query by one of STOP_SENDING/RESET_STREAM/CONNECTION_CLOSE QUIC frames. Those terminated DoQ queries are not properly counted for and keep inflating the number of waiting replies for in-flight queries. When the maximum is reached, it results in silent query drops for new clients needing resolution for already in-flight queries. This vulnerability needs Unbound to be compiled with DoQ support ('--with-libngtcp2') and the 'quic-port' to be configured for the listening interfaces. Additionally, a malicious actor needs access to multiple source IPs to bypass the by-default configured 'wait-limit' option.

CVSS v3
3.7
EG Score
3.7(medium)
EG Risk
17(Track)
EG Risk 17/100SSVC: 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
Severity37% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
19%
KEV
Not listed

Published

July 22, 2026

Last Modified

July 24, 2026

References (1)

Vendor Advisories for CVE-2026-41637(3)

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
redhatunbound-main-1.25.2-0.1.hum12026-07-22redhat

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.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
unbound1.13.1-1 ... 1.25.2-1 (47 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
unbound1.17.1-2 ... 1.26.0-2 (25 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
unbound1.22.0-2 ... 1.26.0-2 (15 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
unbound1.22.0-2 ... 1.25.1-1 (9 versions)1.25.2-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 49× 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 105 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-41637?
CVE-2026-41637 is a low vulnerability published on July 22, 2026. In NLnet Labs Unbound 1.22.0 up to and including 1.25.1, client terminated DNS-over-QUIC (DoQ) queries are not accounted properly by Unbound resulting in low-cost inflation of the waiting number of replies for already in-flight resolution queries. This results in degradation of resolution service…
When was CVE-2026-41637 disclosed?
CVE-2026-41637 was first published in the National Vulnerability Database on July 22, 2026, with the most recent update on July 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-41637 actively exploited?
CVE-2026-41637 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 81.5% of all scored CVEs.
What is the CVSS score of CVE-2026-41637?
CVE-2026-41637 has a CVSS v3 base score of 3.7 (NVD).
How do I remediate CVE-2026-41637?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-41637, 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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