HighFix available
pyjwt — security advisory
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.
- Products
- pyjwt
- Affected versions
- 2.10.1-1, 2.10.1-2, 2.10.1-2+deb13u1, 2.10.1-3, 2.10.1-4, 2.11.0-2, 2.12.1-1, 2.13.0-1, 2.14.0-1, 2.15.0-1, 2.15.1-1, 2.6.0-1, 2.6.0-1+deb12u1, 2.7.0-1
- Fixed versions
- 2.14.0-1
- CVEs
- CVE-2026-102271
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 28 Oct 2026, 03:41 UTC · Revision 1
Source evidence
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.
osv:DEBIAN-CVE-2026-102271
pyjwt
Fixed versions: Not specified
pyjwt
Fixed versions: Not specified
pyjwt
Fixed versions: 2.14.0-1
Complete source record
{
"id": "6702de69571c7349d0a46173bb5f2a944de10d481671f4a6bb37abfc22481448",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-102271",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-102271",
"summary": "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.",
"evidence": "osv:DEBIAN-CVE-2026-102271",
"products": [
{
"name": {
"value": "pyjwt",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.10.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.1-3",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.1-4",
"evidence": "/affected/0/versions"
},
{
"value": "2.11.0-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.12.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.13.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.14.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.15.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.15.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.6.0-1+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "2.7.0-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "pyjwt",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.10.1-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.10.1-2+deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "2.10.1-3",
"evidence": "/affected/1/versions"
},
{
"value": "2.10.1-4",
"evidence": "/affected/1/versions"
},
{
"value": "2.11.0-2",
"evidence": "/affected/1/versions"
},
{
"value": "2.12.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.13.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.14.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.15.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.15.1-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "pyjwt",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.14.0-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "2.10.1-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.10.1-3",
"evidence": "/affected/2/versions"
},
{
"value": "2.10.1-4",
"evidence": "/affected/2/versions"
},
{
"value": "2.11.0-2",
"evidence": "/affected/2/versions"
},
{
"value": "2.12.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.13.0-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2026-102271",
"aliases": [
"DEBIAN-CVE-2026-102271"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "pyjwt",
"purl": "pkg:deb/debian/pyjwt?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"2.10.1-1",
"2.10.1-2",
"2.10.1-3",
"2.10.1-4",
"2.11.0-2",
"2.12.1-1",
"2.13.0-1",
"2.14.0-1",
"2.15.0-1",
"2.15.1-1",
"2.6.0-1",
"2.6.0-1+deb12u1",
"2.7.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-102271.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "pyjwt",
"purl": "pkg:deb/debian/pyjwt?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"2.10.1-2",
"2.10.1-2+deb13u1",
"2.10.1-3",
"2.10.1-4",
"2.11.0-2",
"2.12.1-1",
"2.13.0-1",
"2.14.0-1",
"2.15.0-1",
"2.15.1-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-102271.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.14.0-1"
}
]
}
],
"package": {
"name": "pyjwt",
"purl": "pkg:deb/debian/pyjwt?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"2.10.1-2",
"2.10.1-3",
"2.10.1-4",
"2.11.0-2",
"2.12.1-1",
"2.13.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-102271.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-07T09:47:37.668720888Z",
"provider": "osv",
"upstream": [
"CVE-2026-102271"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-102271"
]
},
"related_cves": [
{
"value": "CVE-2026-102271",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 94674,
"published_at": "2026-09-28T21:17:15.11+00:00"
}