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.
CVE-2026-42505
MEDIUMPre-NVD 5.35.3—Trending — 4 sources updated this week
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
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.3Exploit: NoneExposed: 0
A fix is available — apply it.
- 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 computedSeverity53% × 45%Exploitation0% × 40%Automatability100% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 33.7%
- KEV
- Not listed
Published
July 8, 2026
Last Modified
July 13, 2026
Advisory Details (4)
Auto-updated Jul 8, 2026No patch confirmed yet.
generic
crypto/tls: omit PSK in ECH outer client hello · Issue #79282 · golang/go · GitHub
https://go.dev/issue/79282generic
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.
- CVE-2026-42505Microsoft Security Response Center (MSRC)Medium
Invoking Encrypted Client Hello privacy leak in crypto/tls
- GHSA-ff52-ph69-cf7xGitHub Security AdvisoriesMedium
Handshakes which used Encrypted Client Hello could be de-anonymized by a passive network observer...
- RHSA-2026:36510Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- RHSA-2026:36477Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
Patch Availability(2)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| redhat | golang1-26-main-1.26.5-0.1.hum1 | 2026-07-08 | redhat |
| redhat | golang1-25-main-1.25.12-0.1.hum1 | 2026-07-08 | redhat |
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)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| 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 9× in last 7d / 26× 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.
- 2026-07-23 03:11 UTCEG score recompute
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:24 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-16 19:31 UTCVendor advisory
- 2026-07-16 19:31 UTCGHSA enrichment
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-07-15 17:30 UTCGHSA enrichment
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-14 15:43 UTCGHSA enrichment
- 2026-07-13 22:30 UTCEPSS rescore
- 2026-07-13 13:56 UTCGHSA enrichment
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-12 12:12 UTCGHSA enrichment
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-11 10:28 UTCEG score recompute▲ 5.30
- 2026-07-11 10:28 UTCGHSA enrichment
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-08 19:44 UTCMITRE cvelistV5CVSS v3 → 5.3 · severity → MEDIUM
- 2026-07-08 18:52 UTCNVD update
- 2026-07-08 16:25 UTCEG score recompute
Show 1 moreShow fewer
- 2026-07-08 16:24 UTCMITRE cvelistV5first tracked
Related CVEs(same vendor + same CWE)
Same vendor
10 shownredhat
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 33.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
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
Is Your Infrastructure Affected by CVE-2026-42505?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.