Security Digest · Vulnerability record
CVE-2026-44203: OpenAM has pre-auth Reflected XSS in OAuth2 / OIDC response_mode=form_post via state parameter (FormPostResponse.ftl)
Open Access Management (OpenAM) is an access management solution.
CVSS 8.3 High EPSS 0.6% · p48
Should you act?
Normal patch cycle
No exploitation signal; fix it in your next routine update if you are affected. 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 0.6%, percentile 48: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 48% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Only applies if your dependency tree includes
org.openidentityplatform.openam:openam-oauth2(Maven) >= 13.0.0, < 16.1.1, 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, 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 formpost 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.
From the GitHub advisory
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 formpost response mode. This may allow an attacker to inject content into the rendered page in the context of the OpenAM origin.
Weakness type: CWE-79.
Product: org.openidentityplatform.openam:openam-oauth2 (Maven) · Assigned by: GitHub_M · Published: 2026-09-15
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Maven | org.openidentityplatform.openam:openam-oauth2 | >= 13.0.0, < 16.1.1 | 16.1.1 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| OpenIdentityPlatform | OpenAM | < 16.1.1 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 4.0 | 8.3 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:H/VA:N/SC:L/SI:H/SA:N |
| GitHub | 3.1 | 9.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: none
- Privileges required: none (no login)
- User interaction: active
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): 0.59% probability of exploitation activity in the next 30 days; percentile 48.
Timeline
- — GitHub-reviewed advisory GHSA-fq9h-c788-fx73 published (critical)
- — CVE record published by GitHub_M
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-fq9h-c788-fx73 github.com
- CVE.org record CVE-2026-44203 cve.org
- NVD entry CVE-2026-44203 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com