CVE-2026-4437

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-03-20. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
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.

Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the application to treat a non-answer section of the DNS response as a valid answer.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
24.6%
KEV
Not listed

Published

March 20, 2026

Last Modified

July 14, 2026

Advisory Details (1)

Auto-updated Jun 10, 2026
No patch confirmed yet.
generic

34014 – (CVE-2026-4437) gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response

https://sourceware.org/bugzilla/show_bug.cgi?id=34014

Vendor Advisories for CVE-2026-4437(9)

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

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatinsights-proxy/insights-proxy-container-rhel9:17804204282026-06-02redhat
redhatglibc-0:2.34-270.el9_82026-05-26redhat
redhatglibc-0:2.39-121.el10_22026-05-19redhat
redhatglibc-main-2.42-11.1.hum12026-04-09redhat

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.

Data Freshness Timeline

(refreshed 9× in last 7d / 39× 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.

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

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-4437?
CVE-2026-4437 is a high vulnerability published on March 20, 2026. Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the…
When was CVE-2026-4437 disclosed?
CVE-2026-4437 was first published in the National Vulnerability Database on March 20, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4437 actively exploited?
CVE-2026-4437 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 24.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-4437?
CVE-2026-4437 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-4437?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4437, 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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