CVE-2026-42505

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

Score 5.3 from GitHub Security Advisory published 2026-07-08. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this week
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.3Exploit: None knownExposed: 0

A fix is available — apply it.

Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a disclosure of pre-shared key identities in the unencrypted client hello.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: 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
Severity53% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
32%
KEV
Not listed

Published

July 8, 2026

Last Modified

September 16, 2026

Advisory Details (4)

Auto-updated Jul 8, 2026
No patch confirmed yet.
generic

GO-2026-5856 - Go Packages

https://pkg.go.dev/vuln/GO-2026-5856
generic
https://groups.google.com/g/golang-announce/c/OrmQE_Yp5Sc
generic

crypto/tls: omit PSK in ECH outer client hello · Issue #79282 · golang/go · GitHub

https://go.dev/issue/79282
generic
https://go.dev/cl/775960

Vendor Advisories for CVE-2026-42505(8)

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

Patch Availability(6)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatrhosdt/opentelemetry-rhel9-operator:17866351752026-08-13redhat
redhatgo-toolset:rhel8-8100020260710105056.a3795dee2026-07-13redhat
redhatgolang-0:1.26.5-1.el9_82026-07-09redhat
redhatgolang-0:1.26.5-1.el10_22026-07-09redhat
redhatgolang1-26-main-1.26.5-0.1.hum12026-07-08redhat
redhatgolang1-25-main-1.25.12-0.1.hum12026-07-08redhat

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

(5 across 3 ecosystems)
Debian:14(3)
PackageVulnerable rangeFixed inDependents
golang-1.251.25.0-1 ... 1.25.9-1 (17 versions)1.25.12-1—
golang-1.261.26.0-1 ... 1.26~rc3-2 (15 versions)1.26.5-1—
golang-1.271.27~rc1-11.27~rc2-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
golang-1.241.24.12-1 ... 1.24.9-1 (10 versions)——
Go(1)
PackageVulnerable rangeFixed inDependents
stdlib—1.27.0-rc.2—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 18× in last 7d / 63× 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 184 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-42505?
CVE-2026-42505 is a medium vulnerability published on July 8, 2026. Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer due to a disclosure of pre-shared key identities in the unencrypted client hello.
When was CVE-2026-42505 disclosed?
CVE-2026-42505 was first published in the National Vulnerability Database on July 8, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42505 actively exploited?
CVE-2026-42505 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 67.9% of all scored CVEs.
What is the CVSS score of CVE-2026-42505?
CVE-2026-42505 has a CVSS v3.1 base score of 5.3 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-42505?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42505, 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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