CVE-2026-39831

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 65% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cisa-adp, epss
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.1Exploit: None knownExposed: 0

A fix is available — apply it.

The Verify() method for FIDO/U2F security key types ([email protected], [email protected]) did not check the User Presence flag. Signatures generated without physical touch were accepted, allowing unattended use of a hardware security key. To restore the previous behavior, return a "no-touch-required" extension in Permissions.Extensions from PublicKeyCallback.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
56(Track)
EG Risk 56/100SSVC: 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
Severity91% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
36%
KEV
Not listed

Published

May 22, 2026

Last Modified

July 23, 2026

Advisory Details (4)

Auto-updated Sep 16, 2026
No patch confirmed yet.
generic

GO-2026-5019 - Go Packages

https://pkg.go.dev/vuln/GO-2026-5019
generic
https://groups.google.com/g/golang-announce/c/a082jnz-LvI
generic

x/crypto/ssh: bypass of FIDO/U2F security keys physical interaction · Issue #79566 · golang/go · GitHub

https://go.dev/issue/79566
generic
https://go.dev/cl/781662

Vendor Advisories for CVE-2026-39831(20)

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

Patch Availability(25)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntugoogle-guest-agent (20250116.00-0ubuntu1~24.04.4) @ noble2026-08-23ubuntu
redhatmulticluster-engine/hypershift-addon-rhel9-operator:17869120062026-08-19redhat
redhatopenshift4/ose-machine-api-provider-azure-rhel9:17865497592026-08-18redhat
redhatrhacm2/volsync-rhel9:17864566582026-08-12redhat
redhatmulticluster-engine/hypershift-addon-rhel9-operator:17865483812026-08-12redhat
redhatopenshift-gitops-1/argocd-rhel9:17852113462026-08-10redhat
redhatopenshift-gitops-1/argocd-rhel8:17851492602026-08-10redhat
redhatrhtas/policy-controller-rhel9:17854162882026-08-06redhat
redhatoadp/oadp-velero-rhel9:17851808782026-08-06redhat
redhatrhtas/rekor-cli-rhel9:17853915242026-08-05redhat
redhatrhtas/timestamp-authority-rhel9:17853913832026-08-05redhat
redhatrhtas/model-transparency-cli-rhel9:17854761062026-08-05redhat
redhatrhtas/rekor-monitor-rhel9:17853915022026-08-05redhat
redhatrhtas/model-validation-rhel9-operator:17854879362026-08-05redhat
redhatoadp/oadp-velero-rhel9:17840588222026-07-22redhat
redhatquay/quay-rhel8:17843519662026-07-21redhat
redhatrhtas/rekor-cli-rhel9:17839693652026-07-16redhat
redhatrhtas/rekor-monitor-rhel9:17839685082026-07-16redhat
redhatquay/quay-rhel9:17839558462026-07-16redhat
redhatquay/quay-rhel8:17837504472026-07-16redhat
redhatrhtas/timestamp-authority-rhel9:17839686442026-07-16redhat
redhatquay/quay-rhel8:17841258382026-07-15redhat
redhatodf4/rook-ceph-rhel9-operator:17829342842026-07-09redhat
redhatadvanced-cluster-security/rhacs-scanner-slim-rhel8:17828917892026-07-08redhat
redhatadvanced-cluster-security/rhacs-scanner-v4-rhel8:17833571162026-07-07redhat

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 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
golang-go.crypto1:0.0~git20201221.eec23a3-1 ... 1:0.53.0-1 (40 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
golang-go.crypto1:0.10.0-1 ... 1:0.55.0-1 (35 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
golang-go.crypto1:0.25.0-1 ... 1:0.55.0-1 (20 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
golang-go.crypto1:0.25.0-1 ... 1:0.52.0-1~bpo13+1 (16 versions)1:0.52.0-1—
Go(1)
PackageVulnerable rangeFixed inDependents
golang.org/x/crypto—0.52.0—

Weakness Classification(1)

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

Additional Vendor Advisories

(17)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 8× in last 7d / 37× 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 246 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-39831?
CVE-2026-39831 is a critical vulnerability published on May 22, 2026. The Verify() method for FIDO/U2F security key types ([email protected], [email protected]) did not check the User Presence flag. Signatures generated without physical touch were accepted, allowing unattended use of a hardware security key. To restore the previous behavior,…
When was CVE-2026-39831 disclosed?
CVE-2026-39831 was first published in the National Vulnerability Database on May 22, 2026, with the most recent update on July 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-39831 actively exploited?
CVE-2026-39831 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 64.0% of all scored CVEs.
What is the CVSS score of CVE-2026-39831?
CVE-2026-39831 has a CVSS v3.1 base score of 9.1 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-39831?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-39831, 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-2026-39831

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