PyJWT is a Python implementation of JSON Web Token standards. From 2.13.0 until 2.14.0, PyJWT HMACAlgorithm.prepare_key is affected because HMAC key guard only recognizes top-level public JWK forms and misses container representations. This occurs when an application allows HMAC and asymmetric algorithms and passes a public JWK container as the raw key. As a result, public asymmetric key material is accepted as the HMAC secret. Consequently, an attacker who knows the public key can forge a token with arbitrary authenticated claims. This issue is fixed in version 2.14.0.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-347"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102273.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "2.13.0"
},
{
"fixed": "2.14.0"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "801cd128528c62d9b23fcd161d1a2e1c17982f95"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "2.14.0",
"range": [
{
"fixed": "c6fe464b356ff4b1ebc9ba62172d331a40aa27df"
}
],
"source": "REFERENCES_TAG"
}
]
}