CVE-2026-32597

PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)

At a glance

Severity: HIGH 7.5
EPSS: EPSS 0.27 % · percentile 20 (2026-10-27)
State: PUBLISHED
Published: 2026-03-12
Updated: 2026-09-10
Assigner: GitHub_M
NVD status: Modified

Description

PyJWT is a JSON Web Token implementation in Python. Prior to 2.12.0, PyJWT does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. When a JWS token contains a crit array listing extensions that PyJWT does not understand, the library accepts the token instead of rejecting it. This violates the MUST requirement in the RFC. This vulnerability is fixed in 2.12.0.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N	GitHub_M
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N	redhat-SADP
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N	NVD · security-advisories@github.com (Secondary)
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N	NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary)

Weaknesses (CWE)

Advisories

GHSA-752w-5fwx-jx9f — PyJWT accepts unknown `crit` header extensions
PYSEC-2026-120 — PyJWT is a JSON Web Token implementation in Python. Prior to 2.12.0, PyJWT does not validate the crit (Critical) Header Parameter defined in RFC 7515 §4.1.11. W

European references

ENISA EUVD · EUVD-2026-11728
GCVE · GCVE-0-2026-32597

CERT-FR advisories

CERTFR-2026-AVI-1291 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-1056 — Multiples vulnérabilités dans les produits Splunk · cert.ssi.gouv.fr
CERTFR-2026-AVI-0667 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-0641 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
CERTFR-2026-AVI-0326 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
CERTFR-2026-AVI-0316 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:pyjwt_project:pyjwt:*:*:*:*:*:*:*:* < 2.12.0

Affected products

Product	Versions
jpadilla · pyjwt	affected < 2.12.0

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD