{"id":"CVE-2026-34240","state":"PUBLISHED","title":"jose vulnerable to untrusted JWK header key acceptance during signature verification","description":"JOSE is a Javascript Object Signing and Encryption (JOSE) library. Prior to version 0.3.5+1, a vulnerability in jose could allow an unauthenticated, remote attacker to forge valid JWS/JWT tokens by using a key embedded in the JOSE header (jwk). The vulnerability exists because key selection could treat header-provided jwk as a verification candidate even when that key was not present in the trusted key store. Since JOSE headers are untrusted input, an attacker could exploit this by creating a token payload, embedding an attacker-controlled public key in the header, and signing with the matching private key. Applications using affected versions for token verification are impacted. This issue has been patched in version 0.3.5+1. A workaround for this issue involves rejecting tokens where header jwk is present unless that jwk matches a key already present in the application's trusted key store.","publishedAt":"2026-03-31T15:44:23.578Z","updatedAt":"2026-04-01T14:03:14.969Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["appsup-dart jose"],"affected":[{"vendor":"appsup-dart","product":"jose","versions":[{"version":"< 0.3.5+1","status":"affected"}]}],"references":["https://github.com/appsup-dart/jose/security/advisories/GHSA-vm9r-h74p-hg97","https://github.com/appsup-dart/jose/commit/b07799aac1f56a9a21483feac026272aab30cc5d"],"weaknesses":["CWE-347"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/34xxx/CVE-2026-34240.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-34240","state":"PUBLISHED","datePublished":"2026-03-31T15:44:23.578Z","dateUpdated":"2026-04-01T14:03:14.969Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-03-26T16:22:29.034Z"},"containers":{"cna":{"title":"jose vulnerable to untrusted JWK header key acceptance during signature verification","descriptions":[{"lang":"en","value":"JOSE is a Javascript Object Signing and Encryption (JOSE) library. Prior to version 0.3.5+1, a vulnerability in jose could allow an unauthenticated, remote attacker to forge valid JWS/JWT tokens by using a key embedded in the JOSE header (jwk). The vulnerability exists because key selection could treat header-provided jwk as a verification candidate even when that key was not present in the trusted key store. Since JOSE headers are untrusted input, an attacker could exploit this by creating a token payload, embedding an attacker-controlled public key in the header, and signing with the matching private key. Applications using affected versions for token verification are impacted. This issue has been patched in version 0.3.5+1. A workaround for this issue involves rejecting tokens where header jwk is present unless that jwk matches a key already present in the application's trusted key store."}],"affected":[{"vendor":"appsup-dart","product":"jose","versions":[{"version":"< 0.3.5+1","status":"affected"}]}],"references":[{"url":"https://github.com/appsup-dart/jose/security/advisories/GHSA-vm9r-h74p-hg97","name":"https://github.com/appsup-dart/jose/security/advisories/GHSA-vm9r-h74p-hg97","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/appsup-dart/jose/commit/b07799aac1f56a9a21483feac026272aab30cc5d","name":"https://github.com/appsup-dart/jose/commit/b07799aac1f56a9a21483feac026272aab30cc5d","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-347","lang":"en","description":"CWE-347: Improper Verification of Cryptographic Signature","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-03-31T15:44:23.578Z"},"source":{"advisory":"GHSA-vm9r-h74p-hg97","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-01T14:02:31.709988Z","id":"CVE-2026-34240","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-01T14:03:14.969Z"}}]}}}