How severe is CVE-2026-62263?

No CVSS score has been assigned to CVE-2026-62263 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-62263?

CVE-2026-62263 affects the following packages: org.openidentityplatform.openam:openam-auth-webauthn (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-62263?

Update org.openidentityplatform.openam:openam-auth-webauthn to 16.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-62263 is resolved across your whole dependency graph.

How do I detect CVE-2026-62263 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.openidentityplatform.openam:openam-auth-webauthn, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-62263 if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Is CVE-2026-62263 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-62263 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-62263?

CVE-2026-62263 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 57th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-62263?

CVE-2026-62263 is classified as Deserialization of Untrusted Data (CWE-502). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-62263 published, and has it been updated?

CVE-2026-62263 was published on September 15, 2026 and was last updated on September 25, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕ Maven

Not in CISA KEV

CVE-2026-62263 — openam-auth-webauthn

Fix: OpenIdentityPlatform/OpenAM@9dd0fbe

CVE-2026-62263 is a Deserialization of Untrusted Data vulnerability in org.openidentityplatform.openam:openam-auth-webauthn. A fix is available for org.openidentityplatform.openam:openam-auth-webauthn — see the affected versions and patch details below.

OpenAM: WebAuthn Java deserialization RCE via ObjectInputFilter depth>1 bypass

Also known asGHSA-gf8h-gq53-288j

Published

Sep 15, 2026

Updated

Sep 25, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-62263.

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs57th percentile — riskier than 57% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

☕org.openidentityplatform.openam:openam-auth-webauthn

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Summary

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.openidentityplatform.openam:openam-auth-webauthn`	all versions	16.1.2`org.openidentityplatform.openam:openam-auth-webauthn:16.1.2`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.openidentityplatform.openam:openam-auth-webauthn, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.openidentityplatform.openam:openam-auth-webauthn to 16.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-62263 is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Frequently Asked Questions

### Summary 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`/`readRes

O3 Security · Impact-Aware SCA

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