CVE-2026-102266

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Source
https://cve.org/CVERecord?id=CVE-2026-102266
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-102266.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-102266
Aliases
Downstream
CGA (114)
DEBIAN (1)
ECHO (1)
MINI (3)
UBUNTU (1)
Published
2026-09-28T20:21:26Z
Modified
2026-09-30T11:30:21Z
Severity
  • 7.4 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
Summary
PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation
Details

PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded key without applying prepare_key validation. This occurs when a trusted JWK Set contains an oct entry with an empty k value. As a result, an attacker signs an HMAC token with the same zero-length key accepted by PyJWT. Consequently, forged token can carry arbitrary authenticated claims. This issue is fixed in version 2.14.0.

Database specific 
{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-347"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102266.json"
}
References

Affected packages

Git / github.com/jpadilla/pyjwt

Affected ranges

Type
GIT
Repo
https://github.com/jpadilla/pyjwt
Events
Introduced
7144e4534c34810f4525dc4578a32addd8212cff
Fixed
f91ed44dd65baaf457f4b3353ed35e98a753934c
Fixed
c6fe464b356ff4b1ebc9ba62172d331a40aa27df
Database specific
Show details 
{
    "extracted_events":  [
        {
            "introduced":  "2.13.0"
        },
        {
            "fixed":  "2.14.0"
        }
    ],
    "source":  [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Affected versions

2.*
2.13.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-102266.json"