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Full vulnerability report · 2026
CVE-2026-9689High confidence

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

Red Hat · Red Hat build of Keycloak 26.4

4.2MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-9689 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitykeycloak: org.keycloak.protocol.oidc: HTTP Parameter Pollution in OIDC redirect URI allows response parameter duplication - #GHI-604
20 fixed

The vendor explicitly identifies these products or versions as containing the fix.

  • rhbk/keycloak-operator-bundle@sha256:2c25b3107aee4f1fc25530f099fa683ba3077c185d581e7caa777c4410383085_amd64 as a component of Red Hat build of Keycloak 26.4
  • rhbk/keycloak-rhel9-operator@sha256:0d3ea94f75c1b4528722db2c216ff2267ec17ba16adf3f703afb82354f0fdc68_arm64 as a component of Red Hat build of Keycloak 26.4
  • rhbk/keycloak-rhel9-operator@sha256:330350e0cd77afca88886156c2668ae4bca75865e90362cbcf9657197bfa21e8_amd64 as a component of Red Hat build of Keycloak 26.4
  • rhbk/keycloak-rhel9-operator@sha256:399c59b8e63de5b6aa4e64008644550b98feb0957214e58dc7c6a5246dde3c87_ppc64le as a component of Red Hat build of Keycloak 26.4
  • rhbk/keycloak-rhel9-operator@sha256:f9f35a75d3029edf5ff82351c0b60ad0dd8672c3fa8f22f672954c248f9e0c63_s390x as a component of Red Hat build of Keycloak 26.4
  • rhbk/keycloak-rhel9@sha256:130dfc422476647b5098a317a38964e7ea6a2a3f1a63d91f91dfb993921b356b_ppc64le as a component of Red Hat build of Keycloak 26.4
  • rhbk/keycloak-rhel9@sha256:8a6fd6c12811ce179fc1248c63a152d173c12866b84f8b8364f4f3ed42b7ba58_s390x as a component of Red Hat build of Keycloak 26.4
  • rhbk/keycloak-rhel9@sha256:cc475d34ac199de0908a32efa630c219469076feb74fd970d617c40cc90911f8_arm64 as a component of Red Hat build of Keycloak 26.4
  • rhbk/keycloak-rhel9@sha256:fc0390f65497ad6274f3db55ac796eb792255a8780578ab4d98aec9f42c23bc0_amd64 as a component of Red Hat build of Keycloak 26.4
  • rhbk/keycloak-operator-bundle@sha256:06ee2f18c4218c9a095360efa2023b2080aa81e04a08363dbcb1d14de85a5d0d_amd64 as a component of Red Hat build of Keycloak 26.6
  • rhbk/keycloak-rhel9-operator@sha256:0024d9a0b69b61004a0d35ee25eefc443fe75ce2563b1645ec318caacc0aa23c_s390x as a component of Red Hat build of Keycloak 26.6
  • rhbk/keycloak-rhel9-operator@sha256:2eeef9cec3ee8e3cfdb1c4b7377582b4a5378f852e11872eeb74597ad9ec0615_amd64 as a component of Red Hat build of Keycloak 26.6
Summary
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.
Remediation
Before applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on.
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-32212

No EUVD known-exploited evidence

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.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
4.2 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

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.

What

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.

Why

The product receives a complex input with multiple elements or fields that must be consistent with each other, but it does not validate or incorrectly validates that the input is actually consistent.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The product receives a complex input with multiple elements or fields that must be consistent with each other, but it does not validate or incorrectly validates that the input is actually consistent.

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Validation of Consistency within Input → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-1288 ↗

CWE-1288: Improper Validation of Consistency within Input. The product receives a complex input with multiple elements or fields that must be consistent with each other, but it does not validate or incorrectly validates that the input is actually consistent.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-1288
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-32212Official EUVD mapping

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.

Official EUVD record
BSI · German · WID-SEC-W-2026-1708Keycloak: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Keycloak ausnutzen, um seine Privilegien zu erhöhen, um Informationen offenzulegen, um Sicherheitsvorkehrungen zu umgehen und um einen Denial of Service Angriff durchzuführen.

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
See the vendor and CVE records for the affected range.
Fixed
rhbk/keycloak-operator-bundle@sha256:2c25b3107aee4f1fc25530f099fa683ba3077c185d581e7caa777c4410383085_amd64 as a component of Red Hat build of Keycloak 26.4; rhbk/keycloak-rhel9-operator@sha256:0d3ea94f75c1b4528722db2c216ff2267ec17ba16adf3f703afb82354f0fdc68_arm64 as a component of Red Hat build of Keycloak 26.4; rhbk/keycloak-rhel9-operator@sha256:330350e0cd77afca88886156c2668ae4bca75865e90362cbcf9657197bfa21e8_amd64 as a component of Red Hat build of Keycloak 26.4; rhbk/keycloak-rhel9-operator@sha256:399c59b8e63de5b6aa4e64008644550b98feb0957214e58dc7c6a5246dde3c87_ppc64le as a component of Red Hat build of Keycloak 26.4; rhbk/keycloak-rhel9-operator@sha256:f9f35a75d3029edf5ff82351c0b60ad0dd8672c3fa8f22f672954c248f9e0c63_s390x as a component of Red Hat build of Keycloak 26.4; rhbk/keycloak-rhel9@sha256:130dfc422476647b5098a317a38964e7ea6a2a3f1a63d91f91dfb993921b356b_ppc64le as a component of Red Hat build of Keycloak 26.4; rhbk/keycloak-rhel9@sha256:8a6fd6c12811ce179fc1248c63a152d173c12866b84f8b8364f4f3ed42b7ba58_s390x as a component of Red Hat build of Keycloak 26.4; rhbk/keycloak-rhel9@sha256:cc475d34ac199de0908a32efa630c219469076feb74fd970d617c40cc90911f8_arm64 as a component of Red Hat build of Keycloak 26.4; rhbk/keycloak-rhel9@sha256:fc0390f65497ad6274f3db55ac796eb792255a8780578ab4d98aec9f42c23bc0_amd64 as a component of Red Hat build of Keycloak 26.4; rhbk/keycloak-operator-bundle@sha256:06ee2f18c4218c9a095360efa2023b2080aa81e04a08363dbcb1d14de85a5d0d_amd64 as a component of Red Hat build of Keycloak 26.6; rhbk/keycloak-rhel9-operator@sha256:0024d9a0b69b61004a0d35ee25eefc443fe75ce2563b1645ec318caacc0aa23c_s390x as a component of Red Hat build of Keycloak 26.6; rhbk/keycloak-rhel9-operator@sha256:2eeef9cec3ee8e3cfdb1c4b7377582b4a5378f852e11872eeb74597ad9ec0615_amd64 as a component of Red Hat build of Keycloak 26.6; rhbk/keycloak-rhel9-operator@sha256:37c7d8c5b4bd9649b3da2c0929075c6bd311361667a7eb25eb3f52927b7eca8e_ppc64le as a component of Red Hat build of Keycloak 26.6; rhbk/keycloak-rhel9-operator@sha256:aadf59a1eeb8e64f2f1eea906dd1837fd144d8406b07630a3e2b0c9265c107e7_arm64 as a component of Red Hat build of Keycloak 26.6; rhbk/keycloak-rhel9@sha256:30a9118cf874444aabdf4dd8f84d44cb503f89d8432a652fbb0ba860d3815c4d_ppc64le as a component of Red Hat build of Keycloak 26.6; rhbk/keycloak-rhel9@sha256:7b668bfd2a9a1bd6343fb2e802912eaa72bd7043fa5be6e0a6edc06894c74b63_arm64 as a component of Red Hat build of Keycloak 26.6; rhbk/keycloak-rhel9@sha256:83e1c37e7e5b268c8b516f9c13d064db4fbdcd68d25a542dec0d237665b06705_amd64 as a component of Red Hat build of Keycloak 26.6; rhbk/keycloak-rhel9@sha256:c8203365ded9864afe84f579798eefd5f4a79ee6a4e585e47fcb0d8ea3ce959f_s390x as a component of Red Hat build of Keycloak 26.6; Red Hat build of Keycloak 26.4.14; Red Hat build of Keycloak 26.6.5
Action
Before applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 27 May 2026 · Last source change 20 Aug 2026, 00:54 UTC · CWE-1288 · Improper Validation of Consistency within Input

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-32212
Product sourceCNA
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD modified after enrichment

Missing structured fields: affected versions. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-32212↗Vendor advisory↗Vendor advisory↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-9689 · cve.blacktree.nl