Reference page — cumulative record through Thursday, October 8, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-102271

CVE-2026-102271HIGH

jpadilla pyjwt — PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217 guard

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   H   N   N  U  H  H  N    7.4   .0018    7.0     —

AFFECTED
  Product  Versions              Fixed
  pyjwt    >= 2.4.0, < 2.14.0 –  —

TIMELINE
  Sep 28  Reserved by GitHub_M
  Sep 28  Published (CNA: GitHub_M)
  Oct 6   EXPLOIT PUBLISHED — CVE-2026-102271 (jpadilla pyjwt). Public exploit reference added.

CWE-347 · CNA: GitHub_M · CVSS v3.1 · 3 references · NVD status: Analyzed

Description

PyJWT is a Python implementation of JSON Web Token standards. From 2.4.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because asymmetric-key guard relies on textual markers that are absent from DER encoding. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a DER public key as the shared verification key. As a result, PyJWT uses public DER bytes as an HMAC secret. Consequently, an attacker who knows the public key can forge authenticated HMAC tokens. This issue is fixed in version 2.14.0.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
September 28, 2026	Reserved	Reserved by GitHub_M
September 28, 2026	Published	Published (CNA: GitHub_M)
October 6, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-102271 (jpadilla pyjwt). Public exploit reference added.

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
jpadilla	pyjwt	—	>= 2.4.0, < 2.14.0	—

Weaknesses

CWE-347

References (3)

https://github.com/jpadilla/pyjwt/commit/2798504fa2663364573cf2d1043d8d7fef389499 [Patch]
https://github.com/jpadilla/pyjwt/releases/tag/2.14.0 [Product, Release Notes]
https://github.com/jpadilla/pyjwt/security/advisories/GHSA-p4g4-x82p-q773 [Exploit, Patch, Vendor Advisory]

Authoritative record: CVE-2026-102271 at cve.org

Vendors: jpadilla

Weaknesses: CWE-347

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-102271 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Thursday, October 8, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.