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CVE-2026-9689· NVD / CVE Program· CNA redhat

Keycloak: org.keycloak.protocol.oidc: http parameter pollution in oidc redirect uri allows response parameter duplication - #ghi-604

Noroxi assessment

Priority: Monitor (action score 16/100)

  • 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: 0.43% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. A user must open a link or visit a page. Special conditions such as timing or configuration are required.
  • According to the record, no fixed version is available yet.

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

A flaw was found in Keycloak, an open-source identity and access management solution. When a client application is configured to accept broad redirect Uniform Resource Identifiers (URIs), a remote attacker can manipulate the authentication process by crafting a special web address. If a user clicks this link, the client application might incorrectly prioritize attacker-controlled information over legitimate data. This vulnerability, known as HTTP parameter pollution, could allow an attacker to bypass security measures or gain unauthorized access to resources.

MediumCVSS 4.2 · v3.1—No exploit No fix recorded
Published
May 27, 2026
Updated
Aug 20, 2026
EPSS
0.4% · 36th percentile

Report tools

JSON

Action score

16

Monitor

Low priority for now.

CVSS
16 / 40 · 4.2 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
4.2
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-2026-9689

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

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

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 26.4

    • 26.4.14-1 and laternot affected · rpm
    • 26.4-22 and laternot affected · rpm
    • 26.4-22 and laternot affected · rpm

  • Red Hat Red Hat build of Keycloak 26.4.14

    • all versionsunknown

  • Red Hat Red Hat build of Keycloak 26.6

    • 26.6.5-1 and laternot affected · rpm
    • 26.6-11 and laternot affected · rpm
    • 26.6-11 and laternot affected · rpm

  • Red Hat Red Hat build of Keycloak 26.6.5

    • all versionsunknown

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Mavenorg.keycloak:keycloak-servicesfrom 26.5.0 · up to and including 26.6.4—
Mavenorg.keycloak:keycloak-servicesup to and including 26.4.7—

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-2026-7507May 19, 2026 · Org.keycloak/keycloak-services: session fixation in oidc login flow that can lead to account takeover
    30Monitor
  • ← EarlierCVE-2026-9087May 20, 2026 · Keycloak: cross-session email verification proof not bound to upstream identity in first-broker-login
    32Monitor
  • Later →CVE-2026-9704May 27, 2026 · Keycloak: keycloak: privilege escalation due to oversized subject_token jwt
    35Monitor

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.

  • CVE-2026-1594351 days apartKeycloak-services: keycloak-services: oidc idp update reuses masked client secret after token url change
    22Monitor
  • CVE-2026-1478139 days apartKeycloak-services: keycloak-services: oidc email_verified claim incorrectly applied to userinfo email
    19Monitor
  • CVE-2026-1820965 days apartKeycloak-services: keycloak-services: oidc redirect_uri fragment bypass in http parameter pollution check
    18Monitor

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).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • Special conditions such as timing or configuration are required.

If successful

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

Weakness class (CWE)

CWE-1288 · Improper Validation of Consistency within Input

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/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 (5 more)

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

All records