What is CVE-2026-102273?

CVE-2026-102273 is a high-severity vulnerability in Jpadilla Pyjwt, classified under Improper Verification of Cryptographic Signature. CVSS score: 7.4/10. Published 2026-09-28.

How severe is CVE-2026-102273?

High severity. CVSS v3 base score is 7.4 out of 10.

Vulnerability in Jpadilla Pyjwt

CVE-2026-102273

PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because HMAC key guard only recognizes top-level public JWK forms and misses container representations. This occurs when an application allows HMAC and asymmetric algorithms and passes a public JWK container as the raw key. As a result, public asymmetric key material is accepted as the HMAC secret. Consequently, an attacker who knows the public key can forge a token with arbitrary authenticated claims. This issue is fixed in version 2.14.0.

Published 2026-09-28 · last modified 2026-09-29.

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Jpadilla Pyjwt — versions >= 2.13.0, < 2.14.0

Weakness classification (CWE)

CWE-347 — Improper Verification of Cryptographic Signature

References

Frequently asked questions

What is CVE-2026-102273?: CVE-2026-102273 is a high-severity vulnerability in Jpadilla Pyjwt, classified under Improper Verification of Cryptographic Signature. CVSS score: 7.4/10. Published 2026-09-28.
How severe is CVE-2026-102273?: High severity. CVSS v3 base score is 7.4 out of 10.