---
title: "CVE-2026-62263: OpenAM: WebAuthn Java deserialization RCE via ObjectInputFilter depth>1 bypass"
url: https://erroneo.us/security/cve/CVE-2026-62263/
description: "CVE-2026-62263 (org.openidentityplatform.openam:openam-auth-webauthn (Maven)): Open Access Management (OpenAM) is an access management solution. Prior to…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-09-15
date_modified: 2026-09-15
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-62263"
kev: false
cvss: 9.2
epss: 0.0086
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-62263: OpenAM: WebAuthn Java deserialization RCE via ObjectInputFilter depth>1 bypass

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- 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 0.9% , percentile 58: FIRST’s model estimates a 0.9% chance of exploitation activity in the next 30 days, higher than 58% 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) <= 16.1.1, fixed in 16.1.2 . Check your lockfile, including transitive dependencies.

## What it is

Open Access Management (OpenAM) is an access management solution. Prior to 16.1.2, WebAuthnAuthentication.deserialize applies an ObjectInputFilter that allows every serialized object at depth greater than 1 and therefore constrains only an AuthenticatorImpl root object. A pre-authentication attacker can supply a userHandle whose serialized graph has a valid AuthenticatorImpl root and a nested gadget class, causing readObject or readResolve execution before the cast and assertion verification when a usable gadget is on the classpath. This bypasses the incomplete remediation for the earlier WebAuthn deserialization vulnerability. This issue is fixed in version 16.1.2.

## Affected packages

- Maven `org.openidentityplatform.openam:openam-auth-webauthn` <= 16.1.1 → fixed: 16.1.2

## Affected products (CVE record)

- OpenIdentityPlatform OpenAM: < 16.1.2

## Severity

- GitHub_M CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
- GitHub CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`

## Exploitation

- 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): 0.86% probability of exploitation activity in the next 30 days; percentile 58.

## Sources

- [GitHub Advisory GHSA-gf8h-gq53-288j](https://github.com/advisories/GHSA-gf8h-gq53-288j)
- [CVE.org record CVE-2026-62263](https://www.cve.org/CVERecord?id=CVE-2026-62263)
- [NVD entry CVE-2026-62263](https://nvd.nist.gov/vuln/detail/CVE-2026-62263)
- [github.com](https://github.com/OpenIdentityPlatform/OpenAM/security/advisories/GHSA-gf8h-gq53-288j)
- [github.com](https://github.com/OpenIdentityPlatform/OpenAM/commit/9dd0fbe07f70f118cf45042d3a9ffb32f3c21e08)
- [github.com](https://github.com/OpenIdentityPlatform/OpenAM/releases/tag/16.1.2)

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Source page: https://erroneo.us/security/cve/CVE-2026-62263/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt