CVE-2026-16093: Keycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requ

Routine

MEDIUM 5.4WATCHLISTMITIGATEDOWNGRADEMITIGATE

CVE-2026-16093 is a medium-severity flaw (CVSS 5.4) affecting build of keycloak, data grid, jboss enterprise application platform expansion pack. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Keycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requiring them to use signed JWTs for authentication. A flaw was discovered where this enforcement can be bypassed. An attacker with valid client credentials can provide a fake, unsigned assertion header that tricks the system into thinking the policy requirements have been met. This allows the attacker to authenticate using simpler methods l

Why this priority

On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.4% (top 67%)
CISA exploited list	No
Weakness	CWE-807
Published	2026-07-17
Last modified	2026-09-16

Publisher (CNA): Red Hat, Inc. · Vendor: redhat

Last updated 2026-09-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-17 17:17 UTCPublished CVE record published
2026-09-16 19:17 UTCUpdated Record last modified

redhat build of keycloak MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy build-of-keycloak || rpm -q build-of-keycloak || build-of-keycloak --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

redhat data grid DOWNGRADE

Affected: 8.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

1. Check installed version

apt-cache policy data-grid || rpm -q data-grid || data-grid --version

2. No fixed release: DOWNGRADE to a release before 8.0 (Debian / Ubuntu)

apt-cache madison data-grid sudo apt install data-grid=<VERSION_BEFORE_8.0> sudo apt-mark hold data-grid

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list data-grid sudo dnf downgrade data-grid-<VERSION_BEFORE_8.0> sudo dnf versionlock add data-grid

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

redhat jboss enterprise application platform expansion pack MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy jboss-enterprise-application-platform-expansion-pack || rpm -q jboss-enterprise-application-platform-expansion-pack || jboss-enterprise-application-platform-expansion-pack --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

redhat single sign-on DOWNGRADE

Affected: 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

1. Check installed version

apt-cache policy single-sign-on || rpm -q single-sign-on || single-sign-on --version

2. No fixed release: DOWNGRADE to a release before 7.0 (Debian / Ubuntu)

apt-cache madison single-sign-on sudo apt install single-sign-on=<VERSION_BEFORE_7.0> sudo apt-mark hold single-sign-on

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list single-sign-on sudo dnf downgrade single-sign-on-<VERSION_BEFORE_7.0> sudo dnf versionlock add single-sign-on

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-16093?

build of keycloak: mitigate or apply the listed mitigation; data grid: downgrade or apply the listed mitigation; jboss enterprise application platform expansion pack: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-16093 being exploited?

CVE-2026-16093 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-16093 affect?

CVE-2026-16093 affects build of keycloak, data grid, jboss enterprise application platform expansion pack. Severity is medium (CVSS 5.4). Keycloak provides a mechanism called Client Policies to enforce security requirements on clients, such as requiring them to use signed JWTs for authentication. A flaw was discovered where this enforcement can be bypassed. An attacker with v

How urgent is CVE-2026-16093?

Priority 32/100. On your watchlist

Software pages

Keycloak vulnerabilities · JBoss and WildFly vulnerabilities

Related CVEs

CVE-2026-4634 HIGH 7.5 DOWNGRADE A flaw was found in Keycloak
CVE-2026-4636 HIGH 8.1 DOWNGRADE A flaw was found in Keycloak
CVE-2026-4282 HIGH 7.4 DOWNGRADE A flaw was found in Keycloak
CVE-2026-3872 HIGH 7.3 DOWNGRADE A flaw was found in Keycloak
CVE-2026-37980 MEDIUM 6.9 MITIGATE A flaw was found in Keycloak, specifically in the organization selection login page

References

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