CVE-2026-102266

HIGHPre-NVD 7.47.4—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (6th percentile of EPSS-scored CVEs). 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: epss, secondary
Trending — 4 sources updated this weekElevated
7.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.4Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently, forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0.

CVSS v3
7.4
EG Score
7.4HIGHmedium confidence
EG Risk
49
EG Risk 49/100CISA SSVC

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
Severity74% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
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
0.2%
EPSS %ILE
6th
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

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

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 28, 2026

Last Modified

September 30, 2026

Advisory Details (3)

Auto-updated Sep 28, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github, github_commit.
github_release Patch Available

2.14.0

Patch available: jpadilla/pyjwt 2.14.0

https://github.com/jpadilla/pyjwt/releases/tag/2.14.0
github_commit Patch Available

commit f91ed44dd65b (jpadilla/pyjwt)

Patch available: jpadilla/pyjwt 2.14.0 (contains commit f91ed44dd65b)

https://github.com/jpadilla/pyjwt/commit/f91ed44dd65baaf457f4b3353ed35e98a753934c
github Patch Available🟡 PoC Available

PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation · Advisory · jpadilla/pyjwt · GitHub

https://github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r

Vendor Advisories for CVE-2026-102266(2)

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
pyjwt2.13.02.14.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 21× in last 7d / 21× 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. 2026-10-04 09:11 UTCVendor advisory
  2. 2026-10-03 20:59 UTCEG score recompute
  3. 2026-10-03 20:59 UTCVendor advisory
  4. 2026-10-03 14:25 UTCEPSS rescore
  5. 2026-10-03 08:47 UTCVendor advisory
  6. 2026-10-02 20:34 UTCEG score recompute
  7. 2026-10-02 20:34 UTCVendor advisory
  8. 2026-10-02 08:18 UTCVendor advisory
  9. 2026-10-01 20:07 UTCEG score recompute
  10. 2026-10-01 20:07 UTCVendor advisory
  11. 2026-10-01 19:49 UTCEPSS rescore
  12. 2026-10-01 07:55 UTCVendor advisory
  13. 2026-09-30 19:44 UTCEG score recompute
  14. 2026-09-30 15:02 UTCEPSS rescore
  15. 2026-09-29 20:31 UTCEG score recompute
  16. 2026-09-29 19:44 UTCEG score recompute
  17. 2026-09-29 15:20 UTCEPSS rescore
  18. 2026-09-29 09:29 UTCEG score recompute
  19. 2026-09-28 21:18 UTCEG score recompute
  20. 2026-09-28 20:26 UTCEG score recompute
  21. 2026-09-28 20:26 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-102266?
CVE-2026-102266 is a high vulnerability published on September 28, 2026. PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.fromjwk is affected because PyJWK verification path used the decoded key without applying preparekey validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a…
When was CVE-2026-102266 disclosed?
CVE-2026-102266 was first published on September 28, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-102266 actively exploited?
CVE-2026-102266 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (6th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-102266?
CVE-2026-102266 has a CVSS base score of 7.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-102266?
A fix for CVE-2026-102266 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-102266 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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