@node-oauth/oauth2-server: PKCE code_verifier ABNF not enforced in token exchange allows brute-force redemption of intercepted authorization codes
Exact source revision recorded 23 Oct 2026 15:48:27 UTC. It does not establish the source's current position. Latest evidence.
cve-program · CVE-2026-41213
Published@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.
- Source published
- 23 Apr 2026 18:33:42 UTC
- Source modified
- 25 Apr 2026 01:23:58 UTC
- Observed here
- 23 Oct 2026 15:48:27 UTC
- Source terms
- CVE Program Terms of Use
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CVSS 3.1 · 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N