CVE-2026-45051: OpenAM: Pre-auth RCE via Java Deserialization in WebAuthn Authenticator Storage

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.7%, percentile 52: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 52% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes org.openidentityplatform.openam:openam-auth-webauthn (Maven) <= 16.0.6, fixed in 16.1.1. Check your lockfile, including transitive dependencies.

What it is

Open Access Management (OpenAM) is an access management solution. Prior to 16.1.1, WebAuthnAuthentication loads a serialized AuthenticatorImpl object graph from the configured userAttribute through loadAuthenticators without an ObjectInputFilter. Exploitation requires the WebAuthn flow to be reachable and an attacker to have previously written controlled data to that attribute through delegated administration, provisioning, directory access, legacy REST self-registration, or unsafe configuration. When those non-default conditions hold, the data is deserialized before assertion verification and can execute a classpath gadget in the application server process. This issue is fixed in version 16.1.1.

From the GitHub advisory

Summary

Description

A deserialization of untrusted data vulnerability (CWE-502) exists in OpenAM's WebAuthn authentication module. Under certain conditions, this may allow an attacker to achieve arbitrary code execution in the context of the application server. This affects OpenAM Community Edition through version 16.0.6 and was patched in version 16.1.1.

This is not the default configuration. Exploitation requires that an attacker has previously been able to write attacker-controlled data to a storage attribute read by the WebAuthn module, and that the WebAuthn authentication flow is reachable.

Impact WebAuthn is a modern shipped module, but the vulnerable configuration requires either the default storage attribute to become attacker-writable, or the WebAuthn userAttribute to be set to an attacker-writable string attribute. That is not the default, but it is feasible in deployments because the product exposes the storage attribute as a free-form admin setting and does not warn or enforce that it must be server-managed and non-user-writable. This may exist through delegated administration, provisioning, write access to the backing LDAP/directory user record, legacy REST self-registration, or unsafe reconfiguration of userAttribute.

Weakness type: CWE-502.

Product: org.openidentityplatform.openam:openam-auth-webauthn (Maven) · Assigned by: GitHub_M · Published: 2026-09-15

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: present (depends on deployment conditions)
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.69% probability of exploitation activity in the next 30 days; percentile 52.

Timeline

• 2026-06-24 — GitHub-reviewed advisory GHSA-6c99-87fr-6q7r published (critical)
• 2026-09-15 — CVE record last updated
• 2026-09-15 — CVE record published by GitHub_M

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-6c99-87fr-6q7r github.com
2. CVE.org record CVE-2026-45051 cve.org
3. NVD entry CVE-2026-45051 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com

Critical Maven advisories · Today’s Security Digest