OpenAM has pre-auth Reflected XSS in OAuth2 / OIDC response_mode=form_post via state parameter (FormPostResponse.ftl)

HIGH 8.3CVE-2026-44203 · GHSA-fq9h-c788-fx73 · Published 15/09/2026 · updated 23/09/2026

In short

CVE-2026-44203 is a HIGH (CVSS 8.3) vulnerability affecting org.openidentityplatform.openam:openam-oauth2.
Chance of exploitation in the next 30 days (EPSS): 0.59%, higher than 48.4% of all vulnerabilities.
Fix: update to 16.1.1 or later.

Package	Affected versions	Patched versions
org.openidentityplatform.openam:openam-oauth2 Maven	`≥ 13.0.0, < 16.1.1`	`16.1.1`

Description

Summary

The OAuth 2.0 / OpenID Connect authorization endpoint does not sufficiently sanitize certain user-supplied parameters before incorporating them into the HTML response generated for the form_post response mode. This may allow an attacker to inject content into the rendered page in the context of the OpenAM origin.

NVD description

Open Access Management (OpenAM) is an access management solution. Prior to 16.1.1, the OAuth 2.0 and OpenID Connect authorization endpoint does not sufficiently encode user-supplied parameters before FormPostResponse.ftl and checkSession.ftl render them into HTML for the form_post response mode. An unauthenticated attacker can induce a user to open a crafted authorization request and execute script in the OpenAM origin. This issue is fixed in version 16.1.1.