CVE-2026-56444

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

Score 5.9 from GitHub Security Advisory published 2026-07-22. a secondary CVSS source baseline 5.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.9Exploit: None knownExposed: 0

A fix is available — apply it.

In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout > discard-timeout > 0' (contrary to the suggested values), the discard-timeout branch during the serve expired logic drops an aged client reply without performing the correct accounting for the number of reply addresses for the query. Other identical branches outside of serve expired perform the correct decrement. Since the counter is never decremented in such scenario, it can reach the maximum limit and new clients for duplicate in-flight queries are silently dropped resulting in degradation of resolution service. A malicious actor can exploit the vulnerability by querying the resolver for a client-controlled slow-on-demand authoritative zone that can drive the counter past the threshold. Shipped defaults for 'serve-expired-client-timeout: 1800' and 'discard-timeout: 1900' make the branch unreachable.

CVSS v3
5.9
EG Score
5.9(medium)
EG Risk
42(Track)
EG Risk 42/100SSVC: 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
Severity59% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
18%
KEV
Not listed

Published

July 22, 2026

Last Modified

July 24, 2026

Advisory Details (1)

Auto-updated Jul 22, 2026
No patch confirmed yet.
generic
https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-56444.txt

Vendor Advisories for CVE-2026-56444(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

(5 across 5 ecosystems)
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
unbound—1.25.2-r0—
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 21× in last 7d / 89× 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 193 total refreshes for this CVE.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-56444?
CVE-2026-56444 is a medium vulnerability published on July 22, 2026. In NLnet Labs Unbound 1.20.0 up to and including 1.25.1, when Unbound is configured with 'serve-expired: yes' and 'serve-expired-client-timeout > discard-timeout > 0' (contrary to the suggested values), the discard-timeout branch during the serve expired logic drops an aged client reply without…
When was CVE-2026-56444 disclosed?
CVE-2026-56444 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-2026-56444 actively exploited?
CVE-2026-56444 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 82.3% of all scored CVEs.
What is the CVSS score of CVE-2026-56444?
CVE-2026-56444 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-56444?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56444, 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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