CVE-2026-85394

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreHIGH confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-09-03. a secondary CVSS source baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
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

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

python-jose through 3.5.0 fails to properly validate asymmetric keys in HMAC initialization, accepting DER-encoded public keys that lack PEM armor or SSH prefixes. Attackers holding the service's public key can forge HS256 tokens that pass verification when algorithms are not explicitly restricted. This is an incomplete fix for CVE-2024-33663.

CVSS v3
9.1
EG Score
9.1(high)
EG Risk
41(Track)
EG Risk 41/100SSVC: 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%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
13%
KEV
Not listed

Published

September 3, 2026

Last Modified

September 14, 2026

Advisory Details (6)

Auto-updated Sep 15, 2026
Patch available. Sources: github.
generic

python-jose through 3.5.0 Algorithm Confusion via DER-encoded Public Key as HMAC Secret | Advisories | VulnCheck

https://www.vulncheck.com/advisories/python-jose-through-3.5.0-algorithm-confusion-via-der-encoded-public-key-as-hmac-secret
generic

Algorithm-confusion guard bypassed by DER-encoded public keys (incomplete CVE-2024-33663 fix) · Issue #414 · mpdavis/python-jose · GitHub

https://github.com/mpdavis/python-jose/issues/414
generic

python-jose/jose/utils.py at 018b310ddb8b50dcfd09a0c152117835a21dd656 · mpdavis/python-jose · GitHub

https://github.com/mpdavis/python-jose/blob/018b310ddb8b50dcfd09a0c152117835a21dd656/jose/utils.py
generic

python-jose/jose/backends/native.py at 018b310ddb8b50dcfd09a0c152117835a21dd656 · mpdavis/python-jose · GitHub

https://github.com/mpdavis/python-jose/blob/018b310ddb8b50dcfd09a0c152117835a21dd656/jose/backends/native.py
generic

GitHub - mpdavis/python-jose: A JOSE implementation in Python · GitHub

https://github.com/mpdavis/python-jose
github Patch Available

python-jose algorithm confusion with OpenSSH ECDSA keys · CVE-2024-33663 · GitHub Advisory Database · GitHub

https://github.com/advisories/GHSA-6c5p-j8vq-pqhj

Vendor Advisories for CVE-2026-85394(1)

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

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
python-jose0.1.0 ... 3.3.0 (37 versions)3.4.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 57× in last 7d / 122× 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 122 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-85394?
CVE-2026-85394 is a critical vulnerability published on September 3, 2026. python-jose through 3.5.0 fails to properly validate asymmetric keys in HMAC initialization, accepting DER-encoded public keys that lack PEM armor or SSH prefixes. Attackers holding the service's public key can forge HS256 tokens that pass verification when algorithms are not explicitly restricted.…
When was CVE-2026-85394 disclosed?
CVE-2026-85394 was first published in the National Vulnerability Database on September 3, 2026, with the most recent update on September 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-85394 actively exploited?
CVE-2026-85394 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 86.9% of all scored CVEs.
What is the CVSS score of CVE-2026-85394?
CVE-2026-85394 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-85394?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-85394, 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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