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 — Patch released this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 6.5Exploit: None knownExposed: 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)
EG Risk
29(Track)
EG Risk 29/100SSVC: 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
Severity65% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
47%
KEV
Not listed

Published

June 2, 2026

Last Modified

September 18, 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(30)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatflightctl-0:1.1.4-1.el9em2026-09-16redhat
redhatflightctl-0:1.2.1-1.el92026-09-16redhat
redhatoadp/oadp-velero-rhel9:17888604612026-09-09redhat
redhatrhacm2/subctl-rhel9:17881050722026-09-03redhat
redhatopenshift4/ose-ansible-rhel9-operator:17875543472026-09-03redhat
redhatgolang-0:1.26.5-1.el9_22026-08-31redhat
redhatcluster-observability-operator/perses-rhel9:17875939462026-08-31redhat
redhatbutane-0:0.23.0-5.rhaos4.18.el82026-08-26redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17872423212026-08-26redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17872421082026-08-26redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17872636932026-08-26redhat
redhatrhc-1:0.2.2-1.el9_2.42026-08-26redhat
redhatrhc-1:0.2.4-9.el9_42026-08-26redhat
redhatopenshift4/ose-ansible-rhel9-operator:17867544252026-08-26redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17871708302026-08-26redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17872635842026-08-26redhat
redhatmulticluster-engine/provider-credential-controller-rhel9:17872608212026-08-25redhat
redhatmulticluster-engine/work-rhel9:17872591132026-08-25redhat
redhatmulticluster-engine/provider-credential-controller-rhel9:17871767162026-08-25redhat
redhatmulticluster-engine/provider-credential-controller-rhel9:17866642882026-08-25redhat
redhatmulticluster-engine/provider-credential-controller-rhel9:17871768862026-08-25redhat
redhatmulticluster-engine/provider-credential-controller-rhel9:17872395952026-08-25redhat
redhatgolang-0:1.26.5-1.el9_42026-08-20redhat
redhatmulticluster-engine/work-rhel9:17869072762026-08-19redhat
redhatopenshift4/ose-ansible-rhel9-operator:17865261392026-08-18redhat
redhatweb-terminal/web-terminal-exec-rhel9:17866548712026-08-18redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17866138052026-08-13redhat
redhatcompliance/openshift-compliance-operator-bundle:17863800822026-08-13redhat
redhatcollectd-sensubility-0:0.2.1-1.1.el8ost2026-08-13redhat
redhatexternal-secrets-operator/external-secrets-rhel9:17866146762026-08-13redhat

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

(6 across 5 ecosystems)
Debian:14(2)
PackageVulnerable rangeFixed inDependents
golang-1.251.25.0-1 ... 1.25.9-1 (15 versions)1.25.11-1—
golang-1.261.26.0-1 ... 1.26~rc3-2 (13 versions)1.26.4-1—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
golang-1.151.15.15-1 ... 1.15.9-6 (10 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
golang-1.191.19.10-1 ... 1.19.9-1 (12 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
golang-1.241.24.12-1 ... 1.24.9-1 (10 versions)——
Go(1)
PackageVulnerable rangeFixed inDependents
stdlib—1.26.4—

Weakness Classification(1)

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

All Vendor Advisories

(25)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 23× in last 7d / 115× 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 396 total refreshes for this CVE.

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

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 September 18, 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 1% probability of exploitation in the next 30 days, which ranks it in the top 53.1% of all scored CVEs.
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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-27145

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