Summary
OpenAM: WebAuthn Java deserialization RCE via ObjectInputFilter depth>1 bypass
The GHSA-6c99-87fr-6q7r fix wrapped WebAuthn authenticator deserialization in an ObjectInputFilter meant to allow only AuthenticatorImpl, but it short-circuits to ALLOWED for any object at stream depth > 1. Because the Java serialization filter is consulted for every class in the graph (and depth == 1 only for the root's concrete class), the allowlist constrains only the root and leaves the entire nested graph unchecked.
Impact
An attacker can craft a stream rooted at AuthenticatorImpl with an arbitrary gadget chain nested inside. The gadget's readObject/readResolve executes during readObject(), before the cast and before any assertion verification, enabling remote code execution when a gadget is on the classpath. The deserialization sink is reached pre-authentication via an attacker-chosen userHandle.
Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect. Typical impact: arbitrary code execution or logic abuse.
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.
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Frequently Asked Questions
- What is CVE-2026-62263? CVE-2026-62263 is a critical-severity insecure deserialization vulnerability in org.openidentityplatform.openam:openam-auth-webauthn (maven), affecting versions <= 16.1.1. It is fixed in 16.1.2. Untrusted serialized data is processed by a deserializer that can instantiate arbitrary objects or execute code as a side effect.
- Which versions of org.openidentityplatform.openam:openam-auth-webauthn are affected by CVE-2026-62263? org.openidentityplatform.openam:openam-auth-webauthn (maven) versions <= 16.1.1 is affected.
- Is there a fix for CVE-2026-62263? Yes. CVE-2026-62263 is fixed in 16.1.2. Upgrade to this version or later.
- Is CVE-2026-62263 exploitable, and should I be worried? Whether CVE-2026-62263 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-2026-62263 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-2026-62263? Upgrade
org.openidentityplatform.openam:openam-auth-webauthnto 16.1.2 or later.