CVE-2026-28802

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Source
https://cve.org/CVERecord?id=CVE-2026-28802
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-28802.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-28802
Aliases
Downstream
Related
Published
2026-03-06T06:44:26.402Z
Modified
2026-03-13T15:28:57.570079Z
Severity
  • 7.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P CVSS Calculator
Summary
Authlib: Setting `alg: none` and a blank signature appears to bypass signature verification
Details

Authlib is a Python library which builds OAuth and OpenID Connect servers. From version 1.6.5 to before version 1.6.7, previous tests involving passing a malicious JWT containing alg: none and an empty signature was passing the signature verification step without any changes to the application code when a failure was expected.. This issue has been patched in version 1.6.7.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-347"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28802.json"
}
References

Affected packages

Git / github.com/authlib/authlib

Affected ranges

Type
GIT
Repo
https://github.com/authlib/authlib
Events
Introduced
9ec42561cd1a81b518598d252f8adbcf446f7419
Fixed
38e872a3f5b97d2658507acc8762a4e18adaa50e

Affected versions

v1.*
v1.6.5
v1.6.6

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-28802.json"

Git / github.com/lepture/authlib

Affected ranges

Type
GIT
Repo
https://github.com/lepture/authlib
Events
Introduced
9ec42561cd1a81b518598d252f8adbcf446f7419
Fixed
38e872a3f5b97d2658507acc8762a4e18adaa50e
Database specific 
{
    "versions": [
        {
            "introduced": "1.6.5"
        },
        {
            "fixed": "1.6.7"
        }
    ]
}

Affected versions

v1.*
v1.6.5
v1.6.6

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-28802.json"