CVE-2026-27145

MEDIUMPre-NVD 6.56.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

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 (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory
6.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 6.5Exploit: None knownExposed services: Not assessed

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
6.5MEDIUMmedium confidence
EG Risk
29
EG Risk 29/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity65% × 45%
Impact severity (EG Severity): CVSS 6.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.6% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.6%
EPSS %ILE
47th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.5): severity, escalated by confirmed exploitation. This CVE's 6.5 is its impact severity (EG Severity), not escalated.

EG Severity
6.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

June 2, 2026

Last Modified

September 18, 2026

Advisory Details (4)

Auto-updated Jun 12, 2026
Patch available.
Web page

GO-2026-5037 - Go Packages

https://pkg.go.dev/vuln/GO-2026-5037
Web page

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

https://go.dev/issue/79694

Patch Availability(30)

Vendor / EcosystemFix (by version range) / 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 rangeFix by version rangeDependents
golang-1.251.25.0-1 ... 1.25.9-1 (15 versions)
  • every version up to 1.25.11-1: fixed in 1.25.11-1
—
golang-1.261.26.0-1 ... 1.26~rc3-2 (13 versions)
  • every version up to 1.26.4-1: fixed in 1.26.4-1
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
golang-1.151.15.15-1 ... 1.15.9-6 (10 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
golang-1.191.19.10-1 ... 1.19.9-1 (12 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
golang-1.241.24.12-1 ... 1.24.9-1 (10 versions)
  • every version on: no fix on record
—
Go(1)
PackageVulnerable rangeFix by version rangeDependents
stdlib—
  • every version up to 1.25.11: fixed in 1.25.11
  • 1.26.0-0 up to 1.26.4: fixed in 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 7× in last 7d / 28× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 97 of 423 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 3 repeat rows among the latest 100 are merged into the row they repeat. The 326 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  2. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  3. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  4. 2026-10-18 03:51 UTCEG score recompute
  5. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  6. 2026-10-16 16:41 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  7. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  8. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  9. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  10. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  11. 2026-10-12 16:17 UTCEG score recompute
  12. 2026-10-11 20:00 UTCEG score recompute
  13. 2026-10-11 17:13 UTCEG score recompute
  14. 2026-10-11 14:44 UTCEG score recompute
  15. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  16. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  17. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  18. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  19. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  20. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  21. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  22. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  23. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  24. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  25. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.6% · 46th percentile
Show 72 more
  1. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  2. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  3. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  4. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  5. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  6. 2026-09-18 13:18 UTCVendor advisory
  7. 2026-09-18 13:18 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  8. 2026-09-18 12:19 UTCEG score recompute
  9. 2026-09-18 12:19 UTCVendor advisory
  10. 2026-09-18 12:19 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  11. 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  12. 2026-09-17 12:19 UTCVendor advisory
  13. 2026-09-17 12:19 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  14. 2026-09-17 12:10 UTCEG score recompute
  15. 2026-09-17 12:10 UTCVendor advisory
  16. 2026-09-17 12:10 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  17. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  18. 2026-09-16 12:21 UTCEG score recompute
  19. 2026-09-16 12:21 UTCVendor advisory
  20. 2026-09-16 12:21 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  21. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  22. 2026-09-14 05:41 UTCEG score recompute
  23. 2026-09-14 05:41 UTCVendor advisory
  24. 2026-09-14 05:41 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  25. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  26. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  27. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  28. 2026-09-11 13:24 UTCVendor advisory
  29. 2026-09-11 13:24 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  30. 2026-09-11 12:20 UTCEG score recompute
  31. 2026-09-11 12:20 UTCVendor advisory
  32. 2026-09-11 12:20 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  33. 2026-09-10 13:22 UTCVendor advisory
  34. 2026-09-10 13:22 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  35. 2026-09-10 12:25 UTCEG score recompute
  36. 2026-09-10 12:25 UTCVendor advisory
  37. 2026-09-10 12:25 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  38. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  39. 2026-09-09 12:38 UTCEG score recompute
  40. 2026-09-09 12:38 UTCVendor advisory
  41. 2026-09-09 12:38 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  42. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  43. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  44. 2026-09-07 13:49 UTCVendor advisory
  45. 2026-09-07 13:49 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  46. 2026-09-07 12:35 UTCEG score recompute
  47. 2026-09-07 12:35 UTCVendor advisory
  48. 2026-09-07 12:34 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  49. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  50. 2026-09-04 13:29 UTCVendor advisory
  51. 2026-09-04 13:29 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  52. 2026-09-04 12:21 UTCEG score recompute
  53. 2026-09-04 12:21 UTCVendor advisory
  54. 2026-09-04 12:21 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  55. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  56. 2026-09-03 13:19 UTCVendor advisory
  57. 2026-09-03 13:19 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  58. 2026-09-03 12:28 UTCEG score recompute
  59. 2026-09-03 12:28 UTCVendor advisory
  60. 2026-09-03 12:27 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  61. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  62. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  63. 2026-09-01 13:44 UTCVendor advisory
  64. 2026-09-01 13:44 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  65. 2026-09-01 12:20 UTCEG score recompute
  66. 2026-09-01 12:20 UTCVendor advisory
  67. 2026-09-01 12:19 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  68. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  69. 2026-08-31 13:31 UTCVendor advisory
  70. 2026-08-31 13:31 UTCGHSA enrichmentGHSA-4279-q6mj-392r · GitHub CVSS 6.5
  71. 2026-08-31 12:30 UTCEG score recompute
  72. 2026-08-31 12:30 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-27145?
CVE-2026-27145 is a medium-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-27145 published?
The CVE record for CVE-2026-27145 was published on June 2, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 18, 2026; the record at its source may have been updated since.
Is CVE-2026-27145 actively exploited?
CVE-2026-27145 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (47th percentile of EPSS-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?
A fix for CVE-2026-27145 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-27145 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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