CVE-2026-42505

MEDIUMPre-NVD 5.35.3
EchelonGraph scoreMEDIUM confidence

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

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 (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory
5.3EG
EchelonGraph verdictMonitorRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.3Exploit: None knownExposed services: Not assessed

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
5.3MEDIUMmedium confidence
EG Risk
39
EG Risk 39/100

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)
Severity53% × 45%
Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
30th
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 (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.

EG Severity
5.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.4% 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 low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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 low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (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

July 8, 2026

Last Modified

September 16, 2026

Advisory Details (4)

Auto-updated Jul 8, 2026
Patch available.
Web page

GO-2026-5856 - Go Packages

https://pkg.go.dev/vuln/GO-2026-5856
Web page

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

https://go.dev/issue/79282

Patch Availability(6)

Vendor / EcosystemFix (by version range) / 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 rangeFix by version rangeDependents
golang-1.251.25.0-1 ... 1.25.9-1 (17 versions)
  • every version up to 1.25.12-1: fixed in 1.25.12-1
—
golang-1.261.26.0-1 ... 1.26~rc3-2 (15 versions)
  • every version up to 1.26.5-1: fixed in 1.26.5-1
—
golang-1.271.27~rc1-1
  • every version up to 1.27~rc2-1: fixed in 1.27~rc2-1
—
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 1.25.12: fixed in 1.25.12
  • 1.26.0-0 up to 1.26.5: fixed in 1.26.5
  • 1.27.0-0 up to 1.27.0-rc.2: fixed in 1.27.0-rc.2
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 40× 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 100 of 224 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. None are among the latest 100 rows. The 124 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  2. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  3. 2026-10-18 03:41 UTCEG score recompute
  4. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  5. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  6. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  7. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  8. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  9. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  10. 2026-10-12 16:07 UTCEG score recompute
  11. 2026-10-11 19:49 UTCEG score recompute
  12. 2026-10-11 17:03 UTCEG score recompute
  13. 2026-10-11 14:29 UTCEG score recompute
  14. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  15. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  16. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  17. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  18. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  19. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  20. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  21. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  22. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  23. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  24. 2026-10-01 16:12 UTCEG score recompute
  25. 2026-10-01 16:12 UTCVendor advisory
Show 75 more
  1. 2026-10-01 16:12 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  2. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  3. 2026-09-28 13:23 UTCEG score recompute
  4. 2026-09-28 13:23 UTCVendor advisory
  5. 2026-09-28 13:23 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  6. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  7. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  8. 2026-09-24 11:48 UTCEG score recompute
  9. 2026-09-24 11:48 UTCVendor advisory
  10. 2026-09-24 11:48 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  11. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  12. 2026-09-23 06:11 UTCEG score recompute
  13. 2026-09-23 06:11 UTCVendor advisory
  14. 2026-09-23 06:11 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  15. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  16. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  17. 2026-09-18 05:44 UTCEG score recompute
  18. 2026-09-18 05:44 UTCVendor advisory
  19. 2026-09-18 05:44 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  20. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  21. 2026-09-16 21:11 UTCEG score recompute
  22. 2026-09-16 21:11 UTCVendor advisory
  23. 2026-09-16 21:11 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  24. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  25. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  26. 2026-09-14 11:15 UTCEG score recompute
  27. 2026-09-14 11:15 UTCVendor advisory
  28. 2026-09-14 11:15 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  29. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  30. 2026-09-13 08:25 UTCEG score recompute
  31. 2026-09-13 08:25 UTCVendor advisory
  32. 2026-09-13 08:25 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  33. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  34. 2026-09-12 03:35 UTCEG score recompute
  35. 2026-09-12 03:35 UTCVendor advisory
  36. 2026-09-12 03:35 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  37. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  38. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  39. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  40. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  41. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  42. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  43. 2026-09-05 22:48 UTCEG score recompute
  44. 2026-09-05 22:48 UTCVendor advisory
  45. 2026-09-05 22:48 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  46. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  47. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  48. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  49. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  50. 2026-08-30 07:34 UTCEG score recompute
  51. 2026-08-30 07:34 UTCVendor advisory
  52. 2026-08-30 07:34 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  53. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  54. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  55. 2026-08-27 21:50 UTCEG score recompute
  56. 2026-08-27 21:50 UTCVendor advisory
  57. 2026-08-27 21:50 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  58. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  59. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  60. 2026-08-26 08:24 UTCEG score recompute
  61. 2026-08-26 08:24 UTCVendor advisory
  62. 2026-08-26 08:24 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  63. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  64. 2026-08-24 20:33 UTCEG score recompute
  65. 2026-08-24 20:33 UTCVendor advisory
  66. 2026-08-24 20:33 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  67. 2026-08-23 14:09 UTCEG score recompute
  68. 2026-08-23 14:09 UTCVendor advisory
  69. 2026-08-23 14:09 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  70. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  71. 2026-08-22 12:22 UTCEG score recompute
  72. 2026-08-22 12:22 UTCVendor advisory
  73. 2026-08-22 12:22 UTCGHSA enrichmentGHSA-ff52-ph69-cf7x · GitHub CVSS 5.3
  74. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  75. 2026-08-21 10:27 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-42505?
CVE-2026-42505 is a medium-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-42505 published?
The CVE record for CVE-2026-42505 was published on July 8, 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 16, 2026; the record at its source may have been updated since.
Is CVE-2026-42505 actively exploited?
CVE-2026-42505 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (30th percentile of EPSS-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?
A fix for CVE-2026-42505 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-42505 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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