CVE-2026-75509

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Source
https://cve.org/CVERecord?id=CVE-2026-75509
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-75509.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-75509
Aliases
  • GHSA-r74j-q665-7rpj
Downstream
Published
2026-08-24T20:08:07.088Z
Modified
2026-08-27T11:47:35.685018984Z
Severity
  • 6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N CVSS Calculator
Summary
joserfc claim-validation bypass via array-typed single-string claims (iss/sub/jti)
Details

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.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/75xxx/CVE-2026-75509.json",
    "cwe_ids": [
        "CWE-290",
        "CWE-345"
    ],
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/authlib/joserfc

Affected ranges

Type
GIT
Repo
https://github.com/authlib/joserfc
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
76ee6a59bf5773c0af00b99076c5e199031f97f1
Database specific
Show details 
{
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "1.7.3"
        }
    ]
}

Affected versions

0.*
0.10.0
0.11.0
0.11.1
0.12.0
0.2.0
0.3.0
0.4.0
0.5.0
0.6.0
0.7.0
0.8.0
0.9.0
1.*
1.0.0
1.0.1
1.0.2
1.0.3
1.0.4
1.1.0
1.2.0
1.2.1
1.2.2
1.3.0
1.3.1
1.3.2
1.3.3
1.4.0
1.4.1
1.4.3
1.5.0
1.6.0
1.6.1
1.6.2
1.6.3
1.6.4
1.6.5
1.6.7
1.7.0
1.7.1
1.7.2

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-75509.json"