CVE-2026-15943 (CVSS 5.5)

Description

A flaw was found in the Keycloak keycloak-services component, which handles the management of identity providers. The issue occurs when a delegated administrator updates an OIDC identity provider using a masked client secret sentinel value. Due to improper validation, Keycloak reuses the existing real secret even if security-sensitive fields like the token URL have been changed, allowing an attacker to redirect and capture the secret.

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CVSS v3.1 Score

5.5

MEDIUM

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

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.11%

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-1288 CWE-1288

References

Other References

https://access.redhat.com/security/cve/CVE-2026-15943 https://bugzilla.redhat.com/show_bug.cgi?id=2501270

Frequently Asked Questions

What is CVE-2026-15943? +

A flaw was found in the Keycloak keycloak-services component, which handles the management of identity providers. The issue occurs when a delegated administrator updates an OIDC identity provider using a masked client secret sentinel value. Due to improper validation, Keycloak reuses the existing real secret even if security-sensitive fields like the token URL have been changed, allowing an attacker to redirect and capture the secret. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2026-15943? +

CVE-2026-15943 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-15943? +

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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CVE-2026-15943