Skip to content

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

Critical severity GitHub Reviewed Published Jun 21, 2026 in OpenIdentityPlatform/OpenAM • Updated Jun 22, 2026

Package

maven org.openidentityplatform.openam:openam-oauth2 (Maven)

Affected versions

>= 13.0.0, < 16.1.1

Patched versions

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.

References

@vharseko vharseko published to OpenIdentityPlatform/OpenAM Jun 21, 2026
Published to the GitHub Advisory Database Jun 22, 2026
Reviewed Jun 22, 2026
Last updated Jun 22, 2026

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

EPSS score

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Learn more on MITRE.

CVE ID

CVE-2026-44203

GHSA ID

GHSA-fq9h-c788-fx73

Source code

Credits

Loading Checking history
See something to contribute? Suggest improvements for this vulnerability.