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-2026-102268

CVE-2026-102268CRITICAL

jpadilla pyjwt — PyJWT: Asymmetric-PEM detection bypass: whitespace/line-ending-mutated public keys skip the HS/asymmetric confusion guard

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  H  H  N    9.1   .0020    8.5     —

AFFECTED
  Product  Versions    Fixed
  pyjwt    < 2.14.0 –  —

TIMELINE
  Sep 28  Reserved by GitHub_M
  Sep 28  Published (CNA: GitHub_M)
  Oct 7   EXPLOIT PUBLISHED — CVE-2026-102268 (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. Prior to 2.14.0, is_pem_format in jwt/utils.py is affected because is_pem_format does not recognize every PEM representation accepted by the cryptography loader. This occurs when an application mixes HMAC and asymmetric algorithms and supplies a mutated public-key PEM as raw key bytes. As a result, HMACAlgorithm.prepare_key treats the unrecognized asymmetric public key 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 7, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-102268 (jpadilla pyjwt). Public exploit reference added.

Affected

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

Weaknesses

CWE-347

References (3)

https://github.com/jpadilla/pyjwt/commit/8b4e233a22206b34ec1186e912e75c0b2396ac07 [Patch]
https://github.com/jpadilla/pyjwt/releases/tag/2.14.0 [Product, Release Notes]
https://github.com/jpadilla/pyjwt/security/advisories/GHSA-ffc3-869f-jxw9 [Exploit, Vendor Advisory]

Authoritative record: CVE-2026-102268 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-2026-102268 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.