CVE-2026-93998: Signature Bypass (CVSS 7.4)

Description

A flaw was found in the SAML adapter component of Keycloak, which is used to secure applications with SAML-based authentication. The adapter fails to verify that the issuer of a signed SAML assertion matches the expected identity provider configured for the application. If multiple identity providers share the same trusted signing key, an attacker who controls one of those providers can create a validly signed assertion to log into the application as any user, potentially gaining full administrative control.

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CVSS v3.1 Score

7.4

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0026

Probability of exploitation

0.18%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-347 CWE-347

References

Other References

https://access.redhat.com/errata/RHSA-2026:95759 https://access.redhat.com/errata/RHSA-2026:95760 https://access.redhat.com/errata/RHSA-2026:95761 https://access.redhat.com/errata/RHSA-2026:95762 https://access.redhat.com/security/cve/CVE-2026-93998 https://bugzilla.redhat.com/show_bug.cgi?id=2537164

Frequently Asked Questions

What is CVE-2026-93998? +

A flaw was found in the SAML adapter component of Keycloak, which is used to secure applications with SAML-based authentication. The adapter fails to verify that the issuer of a signed SAML assertion matches the expected identity provider configured for the application. If multiple identity providers share the same trusted signing key, an attacker who controls one of those providers can create a validly signed assertion to log into the application as any user, potentially gaining full administrative control. It has a CVSS v3.1 base score of 7.4 (HIGH).

How severe is CVE-2026-93998? +

CVE-2026-93998 has a CVSS v3.1 score of 7.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0026, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-93998? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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