MediumFix available
joserfc — security advisory
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version 1.7.3, JWTClaimsRegistry applies membership matching to list-valued iss and sub claims, allowing an array-valued iss that contains the expected issuer to pass an intended equality check and enabling issuer-validation bypass. This issue is fixed in version 1.7.3.
- Products
- joserfc
- Affected versions
- 1.1.0-1, 1.2.0-1, 1.2.2-1, 1.3.1-1, 1.3.2-1, 1.3.4-1, 1.4.0-1, 1.4.1-1, 1.4.3-1, 1.5.0-1, 1.6.0-1, 1.6.1-1, 1.6.2-1, 1.6.3-1, 1.6.4-1, 1.6.5-1, 1.6.8-1, 1.7.0-1, 1.7.1-1, 1.7.2-1, 1.7.3-1, 1.7.4-1, 1.7.5-1
- Fixed versions
- 1.7.3-1
- CVEs
- CVE-2026-75509
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 30 Oct 2026, 09:04 UTC · Revision 1
Source evidence
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version 1.7.3, JWTClaimsRegistry applies membership matching to list-valued iss and sub claims, allowing an array-valued iss that contains the expected issuer to pass an intended equality check and enabling issuer-validation bypass. This issue is fixed in version 1.7.3.
osv:DEBIAN-CVE-2026-75509
joserfc
Fixed versions: Not specified
joserfc
Fixed versions: 1.7.3-1
Complete source record
{
"id": "0e888fe34a97cbf0f0ea91756ddb210aa30c7327fdd10654694041c3196769de",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-75509",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-75509",
"summary": "joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to version 1.7.3, JWTClaimsRegistry applies membership matching to list-valued iss and sub claims, allowing an array-valued iss that contains the expected issuer to pass an intended equality check and enabling issuer-validation bypass. This issue is fixed in version 1.7.3.",
"evidence": "osv:DEBIAN-CVE-2026-75509",
"products": [
{
"name": {
"value": "joserfc",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.1.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.2.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.2.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.3.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.3.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.3.4-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.4.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.4.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.4.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.5.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.6.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.6.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.6.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.6.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.6.4-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.6.5-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.6.8-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.7.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.7.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.7.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.7.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.7.4-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.7.5-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "joserfc",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1.7.3-1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": [
{
"value": "1.1.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.2.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.2.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.3.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.3.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.3.4-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.4.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.4.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.4.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.5.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.4-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.5-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.6.8-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.7.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.7.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.7.2-1",
"evidence": "/affected/1/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-75509",
"aliases": [
"DEBIAN-CVE-2026-75509"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "joserfc",
"purl": "pkg:deb/debian/joserfc?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1.1.0-1",
"1.2.0-1",
"1.2.2-1",
"1.3.1-1",
"1.3.2-1",
"1.3.4-1",
"1.4.0-1",
"1.4.1-1",
"1.4.3-1",
"1.5.0-1",
"1.6.0-1",
"1.6.1-1",
"1.6.2-1",
"1.6.3-1",
"1.6.4-1",
"1.6.5-1",
"1.6.8-1",
"1.7.0-1",
"1.7.1-1",
"1.7.2-1",
"1.7.3-1",
"1.7.4-1",
"1.7.5-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-75509.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.7.3-1"
}
]
}
],
"package": {
"name": "joserfc",
"purl": "pkg:deb/debian/joserfc?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1.1.0-1",
"1.2.0-1",
"1.2.2-1",
"1.3.1-1",
"1.3.2-1",
"1.3.4-1",
"1.4.0-1",
"1.4.1-1",
"1.4.3-1",
"1.5.0-1",
"1.6.0-1",
"1.6.1-1",
"1.6.2-1",
"1.6.3-1",
"1.6.4-1",
"1.6.5-1",
"1.6.8-1",
"1.7.0-1",
"1.7.1-1",
"1.7.2-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-75509.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-13T10:00:12.206143601Z",
"provider": "osv",
"upstream": [
"CVE-2026-75509"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-75509"
]
},
"related_cves": [
{
"value": "CVE-2026-75509",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 307605,
"published_at": "2026-08-24T20:17:19.183+00:00"
}