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-2026-102270

CVE-2026-102270MEDIUM

jpadilla pyjwt — PyJWT: ReDoS vulnerability when calling the `is_pem_format` function.

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   H   N  U  N  N  H    4.9   .0021   10.5     —

AFFECTED
  Product  Versions    Fixed
  pyjwt    < 2.14.0 –  —

TIMELINE
  Sep 28  Reserved by GitHub_M
  Sep 28  Published (CNA: GitHub_M)
  Oct 6   EXPLOIT PUBLISHED — CVE-2026-102270 (jpadilla pyjwt). Public exploit reference added.
  Oct 6   RESCORED — CVE-2026-102270 (jpadilla pyjwt). CVSS 4.4 → 4.9 (NVD).

CWE-1333 · 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, PyJWT is_pem_format is affected because lazy PEM regular expression backtracks extensively. This occurs when a certificate-like input contains repeated BEGIN markers without a matching END marker. As a result, is_pem_format performs unbounded backtracking while searching for a PEM end marker. Consequently, an attacker can cause intensive CPU consumption. This issue is fixed in version 2.14.0.

Lifecycle

Complete event history — 4 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-2026-102270 (jpadilla pyjwt). Public exploit reference added.
October 6, 2026	RESCORED	RESCORED — CVE-2026-102270 (jpadilla pyjwt). CVSS 4.4 → 4.9 (NVD).

Affected

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

Weaknesses

CWE-1333

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-jwrc-g2q2-pq5p [Exploit, Patch, Vendor Advisory]

Authoritative record: CVE-2026-102270 at cve.org

Vendors: jpadilla

Weaknesses: CWE-1333

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-102270 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.