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NVD / CVE Program· CNA redhat

CVE-2026-16093: Keycloak-services: keycloak-services: required signed-jwt assertion policy can be bypassed with unsigned assertion headers

Noroxi assessment

Priority: Monitor (action score 21/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.39% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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 like a client secret even when the administrator has mandated more secure, signed assertions.

MediumCVSS 5.4 · v3.1—No exploit No fix recorded
Published
Jul 17, 2026
Updated
Sep 16, 2026
EPSS
0.3% · 33th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
5.4
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-16093

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
redhatbuild of keycloak
redhatdata grid
redhatjboss enterprise application platform expansion pack
redhatsingle sign-on

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • redhat build of keycloakall versions
  • redhat data grid8.0
  • redhat jboss enterprise application platform expansion packall versions
  • redhat single sign-on7.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Red Hat Red Hat build of Keycloak 26.6

    • 26.6.7-3 and laternot affected · rpm
    • 26.6-20 and laternot affected · rpm
    • 26.6-20 and laternot affected · rpm

  • Red Hat Red Hat build of Keycloak 26.6.7

    • all versionsunknown
    • all versionsunknown
    • all versionsunknown

  • Red Hat Red Hat Data Grid 8

    • all versionsaffected

  • Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack

    • all versionsaffected

  • Red Hat Red Hat Single Sign-On 7

    • all versionsaffected

Same product

redhat: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-16442Keycloak-services: keycloak-services: saml idp-initiated broker login bypasses link-only restriction
    39Monitor
  • CVE-2026-16443Keycloak-services: keycloak-services: saml broker metadata import disables response signature validation
    36Monitor
  • CVE-2026-15572Keycloak-services: keycloak-services: dcr protocol mapper type-swap policy bypass allows privilege escalation
    35Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-16072Jul 17, 2026 · Keycloak-services: keycloak-services: organization invitation link exposure allows unauthorized member creation
    19Monitor
  • ← EarlierCVE-2026-16089Jul 17, 2026 · Keycloak-services: keycloak-services: authorization codes can be retargeted to another client session
    23Monitor
  • Later →CVE-2026-16103Jul 17, 2026 · Keycloak-services: keycloak-services: incomplete fix for ciba brute-force lockout bypass at token redemption
    17Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-807 · Reliance on Untrusted Inputs in a Security Decision

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records