9.1

CVE-2026-102266: jpadilla pyjwt

CVSS: 9.1v3.1CriticalAnalyzed
AliasesGHSA-9j54-fg26-wv3rPYSEC-2026-4143UBUNTU-CVE-2026-102266
Published 28-09-2026Last modified 29-09-2026
Open JSON

Vulnerability summary

CVE-2026-102266 is a critical (CVSS 9.1) vulnerability in jpadilla pyjwt. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.3% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.1/10
010
Critical · v3.1 (NVD)
EPSS score
0.18%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 3 · Related 1
OPENSUSE-SU-2026:11994-1USN-8916-1USN-8916-2

Timeline

  1. 28-09-2026
    PublishedVulnerability first disclosed.
  2. 29-09-2026
    Last modifiedVulnerability information updated.

Description

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 metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.18%

Chance of exploitation in the next 30 days

Percentile

7%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

29-09-202619-10-2026
EPSS score
0.18%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • githubUnverified

    Pyjwt

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Chainguard76 products
  • authentik-2026.5< 2026.5.7-r4
  • authentik-fips-2026.5< 2026.5.7-r7
  • azureml-inference-server-httpAll versions (No fix recorded)
  • azureml-inference-server-http-fipsAll versions (No fix recorded)
  • datadog-agent-7.77-core-integrations< 7.77.3-r26
Wolfi11 products
  • datadog-agent-7.77-core-integrations< 7.77.3-r26
  • datadog-agent-7.78-core-integrationsAll versions (No fix recorded)
  • datadog-agent-7.79-core-integrations< 7.79.2-r20
  • datadog-agent-7.80-core-integrations< 7.80.4-r19
  • datadog-agent-7.81-core-integrations< 7.81.3-r8
Debian1 product
  • pyjwtAll versions (No fix recorded) | < 2.14.0-1
Jpadilla1 product
  • pyjwt≥ 2.13.0, < 2.14.0
Pyjwt_project1 product
PyPI1 product
  • pyjwt≥ 2.13.0, < 2.14.0
Ubuntu1 product
  • pyjwtAll versions (No fix recorded)

7 vendors · 92 products

References

11 links
Show all 11 references