CVE-2026-27145

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-06-03. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this week
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 6.5Exploit: NoneExposed: 0

A fix is available — apply it.

(*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the number of SAN entries multiplied by the hostname's label count. Because x509.Verify validates hostnames before building the certificate chain, this overhead occurred even for untrusted certificates.

CVSS v3
6.5
EG Score
6.5(medium)
EPSS
57.2%
KEV
Not listed

Published

June 2, 2026

Last Modified

July 22, 2026

Advisory Details (4)

Auto-updated Jun 12, 2026
No patch confirmed yet.
generic

GO-2026-5037 - Go Packages

https://pkg.go.dev/vuln/GO-2026-5037
generic
https://groups.google.com/g/golang-announce/c/tKs3rmcBcKw
generic

crypto/x509: high-CPU VerifyHostname behavior via repeated hostname splitting · Issue #79694 · golang/go · GitHub

https://go.dev/issue/79694
generic
https://go.dev/cl/783621

Vendor Advisories for CVE-2026-27145(20)

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

Patch Availability(14)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatrhc-1:0.2.7-8.el9_82026-07-15redhat
redhatyggdrasil-0:0.4.9.2-1.el10_22026-07-15redhat
redhatgo-toolset:rhel8-8100020260710105056.a3795dee2026-07-13redhat
redhatrhc-1:0.3.8-6.el10_22026-07-13redhat
redhatconforma-cli-stack-v1-4-1.4.22026-07-09redhat
redhatopenshift-builds/openshift-builds-waiters-rhel9:17830578682026-07-08redhat
redhatskopeo-2:1.22.2-7.el9_82026-07-07redhat
redhatgolang-github-openprinting-ipp-usb-0:0.9.27-7.el10_2.22026-07-06redhat
redhatopentelemetry-collector-0:0.152.1-1.el9_82026-07-01redhat
redhatopentelemetry-collector-0:0.152.1-1.el10_22026-07-01redhat
redhatrhdh/rhdh-rhel9-operator:17827672152026-06-30redhat
redhatgolang-0:1.26.4-1.el9_82026-06-25redhat
redhatgolang1-26-main-1.26.4-2.hum12026-06-04redhat
redhatgolang1-25-main-1.25.11-2.hum12026-06-04redhat

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

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
stdlib—1.26.4—

Weakness Classification(1)

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

Additional Vendor Advisories

(12)

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 15× in last 7d / 71× 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 123 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-27145?
CVE-2026-27145 is a medium vulnerability published on June 2, 2026. (*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the…
When was CVE-2026-27145 disclosed?
CVE-2026-27145 was first published in the National Vulnerability Database on June 2, 2026, with the most recent update on July 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-27145 actively exploited?
CVE-2026-27145 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 57.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-27145?
CVE-2026-27145 has a CVSS v3.1 base score of 6.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-27145?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-27145, 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.

Dependency Blast Radius

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