CVE-2026-107623: Auth Bypass (CVSS 4.3)

Description

A flaw was found in the OIDC Dynamic Client Registration (DCR) component of Keycloak. A bug in the response serialization causes the backchannel logout offline token revocation setting to be omitted from responses. When a client performs a standard update, this missing information causes the setting to be silently disabled. As a result, offline tokens may remain valid even after a user session is terminated via backchannel logout.

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CVSS v3.1 Score

4.3

MEDIUM

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

EPSS — Exploit Prediction

0.0016

Probability of exploitation

0.05%

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-862 Missing Authorization

References

Other References

https://access.redhat.com/security/cve/CVE-2026-107623 https://bugzilla.redhat.com/show_bug.cgi?id=2547957

Frequently Asked Questions

What is CVE-2026-107623? +

A flaw was found in the OIDC Dynamic Client Registration (DCR) component of Keycloak. A bug in the response serialization causes the backchannel logout offline token revocation setting to be omitted from responses. When a client performs a standard update, this missing information causes the setting to be silently disabled. As a result, offline tokens may remain valid even after a user session is terminated via backchannel logout. It has a CVSS v3.1 base score of 4.3 (MEDIUM).

How severe is CVE-2026-107623? +

CVE-2026-107623 has a CVSS v3.1 score of 4.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0016, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-107623? +

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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