How severe is CVE-2023-6927?

CVE-2023-6927 has a CVSS score of 4.6/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-6927?

CVE-2023-6927 affects the following packages: org.keycloak:keycloak-core (Maven). Ecosystems affected: Maven.

How do I fix CVE-2023-6927?

Update org.keycloak:keycloak-core to 23.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-6927 is resolved across your whole dependency graph.

How do I detect CVE-2023-6927 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-6927 if there is no patch (or I can't update yet)?

Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Is CVE-2023-6927 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-6927 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-6927?

CVE-2023-6927 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 66th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-6927?

CVE-2023-6927 is classified as Open Redirect (CWE-601). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-6927 published, and has it been updated?

CVE-2023-6927 was published on December 18, 2023 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2023-6927 — keycloak-core

MEDIUM

CVE-2023-6927 is a medium-severity (CVSS 4.6) Open Redirect vulnerability in org.keycloak:keycloak-core. A fix is available for org.keycloak:keycloak-core — see the affected versions and patch details below.

Keycloak: open redirect via "form_post.jwt" jarm response mode

Also known asGHSA-9vm7-v8wj-3fqw

Published

Dec 18, 2023

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs66th percentile — riskier than 66% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

☕org.keycloak:keycloak-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

An incomplete fix was found in Keycloak Core patch. An attacker can steal authorization codes or tokens from clients using a wildcard in the JARM response mode "form_post.jwt". It is observed that changing the response_mode parameter in the original proof of concept from "form_post" to "form_post.jwt" can bypass the security patch implemented to address CVE-2023-6134.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.keycloak:keycloak-core`	all versions	23.0.4`org.keycloak:keycloak-core:23.0.4`

Affected Products

2 products · 2 configurations

Application

keycloakredhat

all

Application

single sign-onredhat

1 version

7.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.keycloak:keycloak-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.keycloak:keycloak-core to 23.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-6927 is resolved across your whole dependency graph.
Workarounds
Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Red Hat rates this as a moderate, following the same case for CVE-2023-6134, but with another response mode with JSON Web Token.

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Source: Red Hat security advisory for CVE-2023-6927 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat build of Keycloak 22	`rhbk/keycloak-rhel9:22-7`	RHSA-2024:0100
Red Hat build of Keycloak 22.0.8	`keycloak-core`	RHSA-2024:0101
Red Hat Single Sign-On 7	`rh-sso7-keycloak`	RHSA-2024:0804
Red Hat Single Sign-On 7.6 for RHEL 7	`rh-sso7-keycloak-0:18.0.11-3.redhat_00001.1.el7sso`	RHSA-2024:0094
Red Hat Single Sign-On 7.6 for RHEL 7	`rh-sso7-keycloak-0:18.0.12-1.redhat_00001.1.el7sso`	RHSA-2024:0798
Red Hat Single Sign-On 7.6 for RHEL 8	`rh-sso7-keycloak-0:18.0.11-3.redhat_00001.1.el8sso`	RHSA-2024:0095
Red Hat Single Sign-On 7.6 for RHEL 8	`rh-sso7-keycloak-0:18.0.12-1.redhat_00001.1.el8sso`	RHSA-2024:0799
Red Hat Single Sign-On 7.6 for RHEL 9	`rh-sso7-keycloak-0:18.0.11-3.redhat_00001.1.el9sso`	RHSA-2024:0096

Frequently Asked Questions

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