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
46%
KEV
Not listed

Published

June 2, 2026

Last Modified

September 4, 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
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
redhatrhc-1:0.2.4-9.el9_42026-08-26redhat
redhatopenshift4/ose-ansible-rhel9-operator:17867544252026-08-26redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17872421082026-08-26redhat
redhatrhc-1:0.2.2-1.el9_2.42026-08-26redhat
redhatbutane-0:0.23.0-5.rhaos4.18.el82026-08-26redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17872635842026-08-26redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17872636932026-08-26redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17872423212026-08-26redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17871708302026-08-26redhat
redhatmulticluster-engine/work-rhel9:17872591132026-08-25redhat
redhatmulticluster-engine/provider-credential-controller-rhel9:17872395952026-08-25redhat
redhatmulticluster-engine/provider-credential-controller-rhel9:17872608212026-08-25redhat
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
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
redhatexternal-secrets-operator/external-secrets-rhel9:17866146762026-08-13redhat
redhatcollectd-sensubility-0:0.2.1-1.1.el8ost2026-08-13redhat
redhatcert-manager/jetstack-cert-manager-rhel9:17866138052026-08-13redhat
redhatcompliance/openshift-compliance-operator-bundle:17863800822026-08-13redhat
redhatrhc-1:0.2.7-1.el9_6.52026-08-12redhat
redhatrhc-worker-playbook-0:0.2.3-6.el10_02026-08-12redhat
redhatrhacm2/multicluster-operators-subscription-rhel9:17865495372026-08-12redhat

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 27× in last 7d / 146× 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 351 total refreshes for this CVE.

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

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 4, 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 53.9% 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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