CVE-2026-41213
Published: 23 April 2026
Summary
CVE-2026-41213 is a medium-severity Improper Restriction of Excessive Authentication Attempts (CWE-307) vulnerability in Node-Oauth Node-Oauth\/Oauth2-Server. Its CVSS base score is 5.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Brute Force (T1110); ranked at the 36.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-25272
Vulnerability 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…
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code, an attacker who intercepts an authorization code can brute-force code_verifier guesses online until token issuance succeeds.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability enables online brute-force guessing of short code_verifier values against the token endpoint (CWE-307) without code consumption on failure.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
This control directly enforces limits on consecutive invalid logon attempts and automatic response (e.g., lockout) to prevent brute-force exploitation of authentication mechanisms.
Specific conditions can include excessive failed attempts, triggering stronger authentication that restricts brute-force exploitation.