CVE intelligence and bounded remediation
CVE-2026-41213 — @node-oauth/oauth2-server is a module for implementing an OAuth2 server in Node.js
@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.
- Severity
- Medium
- CVSS
- 5.9 (3.1)
- Published
- 2026-04-23
- CISA KEV
- Not currently listed
- Ecosystem
- javascript/npm
- Weaknesses
- CWE-307, CWE-1289
Affected products
- node-oauth / node-oauth/oauth2-server
Matched remediation archetype
Authentication bypass and missing authentication
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
- Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
- Review session, token, credential, and proxy trust configuration without attempting account takeover.
Remediate safely
- Apply the supported fix and centralize fail-closed authentication before protected request handling.
- Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
- Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.
Authoritative sources
Complete CVE record and remediation plan
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