{"id":"CVE-2026-41213","aliases":["GHSA-jhm7-29pj-4xvf"],"url":"https://o3.security/vulnerability/CVE-2026-41213","summary":"@node-oauth/oauth2-server: PKCE code_verifier ABNF not enforced in token exchange allows brute-force redemption of intercepted authorization codes","details":"@node-oauth/oauth2-server is a module for implementing an OAuth2 server in Node.js. The token exchange path accepts RFC7636-invalid code_verifier values (including one-character strings) for S256 PKCE flows. Because short/weak verifiers are accepted and failed verifier attempts do not consume the authorization code, an attacker who intercepts an authorization code can brute-force code_verifier guesses online until token issuance succeeds.","published":"2026-04-23T18:33:42.365Z","modified":"2026-08-12T03:51:12.273320977Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},"epss":{"score":0.00259,"percentile":0.17572,"asOf":"2026-08-12"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"@node-oauth/oauth2-server","fixedVersion":"5.3.0"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/41xxx/CVE-2026-41213.json"},{"type":"ADVISORY","url":"https://github.com/node-oauth/node-oauth2-server/security/advisories/GHSA-jhm7-29pj-4xvf"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41213"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:12.273320977Z"}}