Summary
OpenID Connect nonce generated but never validated, ID token replay attack
The roadiz/openid package generates an OIDC nonce in OAuth2LinkGenerator::generate() and includes it in the authorization request sent to the identity provider, but never stores it and never validates it on the callback. The OpenIdJwtConfigurationFactory validation chain does not include a nonce constraint, and OpenIdAuthenticator::authenticate() never checks the nonce claim in the returned ID token against a stored value.
Details
In src/OAuth2LinkGenerator.php, a nonce is created and sent to the IdP:
'nonce' => $this->tokenGenerator->generateToken(),
However, this value is neither stored in session, cache, nor any other persistent store.
In src/OpenIdJwtConfigurationFactory.php, the JWT validation constraints are:
LooseValidAt(expiry)PermittedFor(audience)IssuedBy(issuer)HostedDomain(optional)UserInfoEndpoint(optional)
No nonce constraint is present.
In src/Authentication/OpenIdAuthenticator.php, the authenticate() method validates the state CSRF token correctly (fixed in v2.7.10), but never retrieves a stored nonce or compares it against the nonce claim in the ID token.
PoC
- Obtain a valid ID token from a legitimate OIDC flow for a target user (e.g. via network interception, browser history leak, or referrer header exposure on a non-HTTPS redirect).
- Replay the ID token: Since the nonce in the token is never cross-checked against a client-stored value, the token passes all validation constraints as long as it has not expired.
- Result: An attacker can authenticate as the victim within the ID token's validity window.
Additionally, in an authorization code flow with multiple concurrent sessions, a malicious IdP or a compromised token endpoint could inject a token with a mismatched nonce, and the application would accept it silently.
Impact
- ID token replay attacks: Valid but intercepted tokens can be reused for authentication within their validity period.
- Token injection attacks: A malicious or compromised identity provider can inject tokens across sessions without detection.
- Affects any Roadiz application using the
roadiz/openidpackage with OpenID Connect SSO.
The OIDC Core 1.0 specification (Section 3.1.3.7) explicitly requires clients to verify the nonce claim if it was present in the authorization request.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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roadiz/openid to 2.7.18 or later; roadiz/openid to 2.6.31 or later; roadiz/openid to 2.5.45 or later; roadiz/openid to 2.3.43 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-42206? CVE-2026-42206 is a medium-severity security vulnerability in roadiz/openid (composer), affecting versions >= 2.7.0, < 2.7.18. It is fixed in 2.7.18, 2.6.31, 2.5.45, 2.3.43.
- Which versions of roadiz/openid are affected by CVE-2026-42206? roadiz/openid (composer) versions >= 2.7.0, < 2.7.18 is affected.
- Is there a fix for CVE-2026-42206? Yes. CVE-2026-42206 is fixed in 2.7.18, 2.6.31, 2.5.45, 2.3.43. Upgrade to this version or later.
- Is CVE-2026-42206 exploitable, and should I be worried? Whether CVE-2026-42206 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-42206 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-42206?
- Upgrade
roadiz/openidto 2.7.18 or later - Upgrade
roadiz/openidto 2.6.31 or later - Upgrade
roadiz/openidto 2.5.45 or later - Upgrade
roadiz/openidto 2.3.43 or later
- Upgrade