CVE-2026-42505

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreHIGH 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(high)
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
17%
KEV
Not listed

Published

July 8, 2026

Last Modified

July 13, 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(4)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
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

(1 across 1 ecosystem)
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 16× in last 7d / 38× 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.

  1. 2026-07-27 15:39 UTCEG score recompute
  2. 2026-07-27 15:39 UTCVendor advisory
  3. 2026-07-27 15:39 UTCGHSA enrichment
  4. 2026-07-27 14:13 UTCEPSS rescore
  5. 2026-07-26 14:54 UTCEPSS rescore
  6. 2026-07-26 14:54 UTCEPSS rescore
  7. 2026-07-26 12:27 UTCEG score recompute
  8. 2026-07-26 12:27 UTCVendor advisory
  9. 2026-07-26 12:27 UTCGHSA enrichment
  10. 2026-07-25 14:18 UTCEPSS rescore
  11. 2026-07-24 14:17 UTCEPSS rescore
  12. 2026-07-23 14:18 UTCEPSS rescore
  13. 2026-07-23 03:11 UTCEG score recompute
  14. 2026-07-22 14:08 UTCEPSS rescore
  15. 2026-07-21 15:24 UTCEPSS rescore
  16. 2026-07-20 17:08 UTCEPSS rescore
  17. 2026-07-19 02:29 UTCEPSS rescore
  18. 2026-07-18 10:04 UTCEPSS rescore
  19. 2026-07-16 19:31 UTCVendor advisory
  20. 2026-07-16 19:31 UTCGHSA enrichment
  21. 2026-07-16 17:03 UTCEPSS rescore
  22. 2026-07-15 17:30 UTCGHSA enrichment
  23. 2026-07-15 16:57 UTCEPSS rescore
  24. 2026-07-15 02:00 UTCEPSS rescore
  25. 2026-07-14 15:43 UTCGHSA enrichment
Show 13 more
  1. 2026-07-13 22:30 UTCEPSS rescore
  2. 2026-07-13 13:56 UTCGHSA enrichment
  3. 2026-07-13 06:13 UTCEPSS rescore
  4. 2026-07-12 12:12 UTCGHSA enrichment
  5. 2026-07-12 05:46 UTCEPSS rescore
  6. 2026-07-11 10:28 UTCEG score recompute▲ 5.30
  7. 2026-07-11 10:28 UTCGHSA enrichment
  8. 2026-07-11 08:27 UTCEPSS rescore
  9. 2026-07-09 19:10 UTCEPSS rescore
  10. 2026-07-08 19:44 UTCMITRE cvelistV5CVSS v3 → 5.3 · severity → MEDIUM
  11. 2026-07-08 18:52 UTCNVD update
  12. 2026-07-08 16:25 UTCEG score recompute
  13. 2026-07-08 16:24 UTCMITRE cvelistV5first tracked

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 July 13, 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 83.1% 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-42505

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