What is CVE-2026-123540?

CVE-2026-123540 is a low-severity vulnerability in Openidentityplatform Openam, classified under Improper Encoding or Escaping of Output. CVSS score: 2.0/10. Published 2026-11-08.

How severe is CVE-2026-123540?

Low severity. CVSS v3 base score is 2.0 out of 10.

Vulnerability in Openidentityplatform Openam

CVE-2026-123540

OpenAM before 16.1.4 contains an incomplete output encoding vulnerability that allows a SAML 1.x identity provider to alter attribute values by injecting unencoded content into the service provider auto-submitted form. Attackers controlling a trusted identity provider can craft assertion attribute names or values that reach the target application in modified form, undermining the integrity of received attributes.

Published 2026-11-08.

CVSS v3 metric

CVSS v3 base score 2.0 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (8.1th percentile), scored 2026-11-09.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 8th percentile — 8.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

The 30-day trend appears once there are two daily scores.

Affected products

Openidentityplatform Openam

Weakness classification (CWE)

CWE-116 — Improper Encoding or Escaping of Output

References

github.com/OpenIdentityPlatform/OpenAM/security/advisories/GHSA-pw99-8h4m-p3gm (vendor-advisory)
www.vulncheck.com/advisories/openam-before-16.1.4-incomplete-attribute-encoding… (third-party-advisory)

Frequently asked questions

What is CVE-2026-123540?: CVE-2026-123540 is a low-severity vulnerability in Openidentityplatform Openam, classified under Improper Encoding or Escaping of Output. CVSS score: 2.0/10. Published 2026-11-08.
How severe is CVE-2026-123540?: Low severity. CVSS v3 base score is 2.0 out of 10.