CVE-2026-44390

MEDIUMNVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

Score 5.3 from GitHub Security Advisory published 2026-05-20. NVD baseline CVSS 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 5.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability when handling replies with very large RRsets that Unbound needs to perform name compression for. Malicious upstream responses with very large RRsets with records that don't share a suffix above the root can cause Unbound to spend a considerable time applying name compression to downstream replies. This can lead to degraded performance and eventually denial of service in well orchestrated attacks. An adversary can exploit the vulnerability by querying Unbound for the specially crafted contents of a malicious zone with very large RRsets. Before Unbound replies to the query it will try to apply name compression which was an unbounded operation that could lock the CPU until the whole packet was complete. A compression limit was introduced in 1.21.1 for this but it didn't account for the case where records would not share any suffix above the root. That causes Unbound to go in a different code path because of the compression tree lookup failure and eventually not increment the compression counter for those operations. Unbound 1.25.1 contains a patch with a fix that increments the compression counter regardless of the compression tree lookup. This is a complement fix to CVE-2024-8508.

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
39
EG Risk 39/100

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
Severity53% × 45%
Exploitation1% × 40%
Automatability100% × 15%
EPSS PROB
0.7%
EPSS %ILE
52nd
KEV
Not listed

Published

May 20, 2026

Last Modified

September 1, 2026

Advisory Details (1)

Auto-updated May 20, 2026
Patch available.
generic
https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-44390.txt

Vendor Advisories for CVE-2026-44390(6)

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

Patch Availability(5)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntuunbound-host (1.24.2-1ubuntu2.1) @ resolute2026-08-25ubuntu
redhatunbound-0:1.16.2-5.12.el8_102026-07-09redhat
redhatunbound-0:1.24.2-3.el9_8.22026-07-08redhat
redhatunbound-0:1.24.2-7.el10_2.22026-07-07redhat
redhatunbound-main-1.25.1-2.hum12026-06-07redhat

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

(7 across 7 ecosystems)
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.25.2-r0: fixed in 1.25.2-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.25.2-r0: fixed in 1.25.2-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
unbound—
  • every version up to 1.25.1-r0: fixed in 1.25.1-r0
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
unbound1.13.1-1 ... 1.25.2-1 (47 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
unbound1.17.1-2 ... 1.26.1-1 (26 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
unbound1.22.0-2, 1.22.0-2+deb13u1, 1.22.0-2+deb13u2
  • every version up to 1.22.0-2+deb13u3: fixed in 1.22.0-2+deb13u3
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
unbound1.22.0-2 ... 1.25.0-1 (8 versions)
  • every version up to 1.25.1-1: fixed in 1.25.1-1
—

Weakness Classification(2)

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 7× in last 7d / 23× 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 259 total refreshes for this CVE.

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

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-44390?
CVE-2026-44390 is a medium vulnerability published on May 20, 2026. NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability when handling replies with very large RRsets that Unbound needs to perform name compression for. Malicious upstream responses with very large RRsets with records that don't share a suffix above the root can cause Unbound to…
When was CVE-2026-44390 disclosed?
CVE-2026-44390 was first published on May 20, 2026, with the most recent update on September 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-44390 actively exploited?
CVE-2026-44390 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (52nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-44390?
CVE-2026-44390 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-44390?
A fix for CVE-2026-44390 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-44390 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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