High
PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-32597
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 2 Nov 2026, 18:13 UTC · Revision 1
Source evidence
PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)
core-osv · Original sourcePublished 12 Mar 2026, 21:41 UTC
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.
osv:CVE-2026-32597
Complete source record
{
"id": "a220688e4ed2c4d372b9e03d0320ff7ede759f1865d0245d384e7a85dec6c882",
"url": "https://osv.dev/vulnerability/CVE-2026-32597",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)",
"summary": "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.",
"evidence": "osv:CVE-2026-32597",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2026-32597",
"aliases": [
"CVE-2026-32597",
"GHSA-752w-5fwx-jx9f",
"PYSEC-2026-120"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/jpadilla/pyjwt",
"type": "GIT",
"events": [
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{
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{
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"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
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{
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"range": [
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"versions": [
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"database_specific": {
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],
"modified": "2026-10-28T02:30:22.048858161Z",
"provider": "osv",
"references": [
"https://lists.debian.org/debian-lts-announce/2026/05/msg00008.html",
"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32597.json",
"https://access.redhat.com/errata/RHSA-2026:10140",
"https://access.redhat.com/errata/RHSA-2026:10141",
"https://access.redhat.com/errata/RHSA-2026:10184",
"https://access.redhat.com/errata/RHSA-2026:12176",
"https://access.redhat.com/errata/RHSA-2026:13508",
"https://access.redhat.com/errata/RHSA-2026:13512",
"https://access.redhat.com/errata/RHSA-2026:13545",
"https://access.redhat.com/errata/RHSA-2026:13553",
"https://access.redhat.com/errata/RHSA-2026:13672",
"https://access.redhat.com/errata/RHSA-2026:13916",
"https://access.redhat.com/errata/RHSA-2026:17083",
"https://access.redhat.com/errata/RHSA-2026:19138",
"https://access.redhat.com/errata/RHSA-2026:19355",
"https://access.redhat.com/errata/RHSA-2026:19375",
"https://access.redhat.com/errata/RHSA-2026:19712",
"https://access.redhat.com/errata/RHSA-2026:21431",
"https://access.redhat.com/errata/RHSA-2026:21517",
"https://access.redhat.com/errata/RHSA-2026:22330",
"https://access.redhat.com/errata/RHSA-2026:24977",
"https://access.redhat.com/errata/RHSA-2026:26226",
"https://access.redhat.com/errata/RHSA-2026:37275",
"https://access.redhat.com/errata/RHSA-2026:42644",
"https://access.redhat.com/errata/RHSA-2026:6568",
"https://access.redhat.com/errata/RHSA-2026:6720",
"https://access.redhat.com/errata/RHSA-2026:6912",
"https://access.redhat.com/errata/RHSA-2026:6926",
"https://access.redhat.com/errata/RHSA-2026:8437",
"https://access.redhat.com/errata/RHSA-2026:8746",
"https://access.redhat.com/errata/RHSA-2026:8747",
"https://access.redhat.com/errata/RHSA-2026:8748",
"https://access.redhat.com/security/cve/CVE-2026-32597",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32597.json",
"https://github.com/jpadilla/pyjwt/security/advisories/GHSA-752w-5fwx-jx9f",
"https://nvd.nist.gov/vuln/detail/CVE-2026-32597",
"https://bugzilla.redhat.com/show_bug.cgi?id=2447194"
],
"provider_metadata": {
"cwe_ids": [
"CWE-345",
"CWE-863"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32597.json"
}
},
"related_cves": [
{
"value": "CVE-2026-32597",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 488193,
"published_at": "2026-03-12T21:41:50.427+00:00"
}