LiveActive security incident?Get immediate response
CVE Record

CVE-2026-2603: Keycloak: keycloak: unauthorized authentication via disabled saml identity provider

A flaw was found in Keycloak. A remote attacker could bypass security controls by sending a valid SAML response from an external Identity Provider (IdP) to the Keycloak SAML endpoint for IdP-initiated broker logins. This allows the attacker to complete broker logins even when the SAML Identity Provider is disabled, leading to unauthorized authentication.

HighCVSS 8.1Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-2603 lets a remote attacker authenticate through Keycloak using a disabled SAML identity provider if they can supply a valid SAML response. The business risk is unauthorized access to applications that trust Keycloak for login. Red Hat rates this high severity with potential confidentiality and integrity impact.

Executive priority

Treat as high priority for any Keycloak-backed authentication estate using SAML brokering. The issue can bypass an intended access-control state and may grant unauthorized application access, but supplied sources do not indicate known active exploitation.

Technical view

The flaw affects Red Hat build of Keycloak 26.2 and 26.4 packages. In IdP-initiated SAML broker login handling, Keycloak can accept a valid external IdP response even when that SAML IdP is disabled. This is mapped to CWE-306 and has CVSS 8.1: network, low complexity, low privileges, no user interaction.

Likely exposure

Exposure is most likely where Red Hat build of Keycloak 26.2 or 26.4 uses SAML identity brokering and disabled SAML IdPs remain configured. The supplied data names affected RHBK packages and operator bundles; it does not prove all upstream Keycloak builds are affected.

Exploitation context

The supplied bundle does not show CISA KEV listing or active exploitation. Exploitation requires a valid SAML response from an external IdP and access to the Keycloak SAML endpoint for IdP-initiated broker login.

Researcher notes

Focus validation on IdP-initiated SAML broker login paths and enforcement of disabled IdP state. Avoid assuming broader product impact beyond the Red Hat build package data provided. Evidence is strong for affected Red Hat builds, but incomplete for exploit prevalence.

Mitigation direction

  • Apply the relevant Red Hat security advisory updates for RHSA-2026:3925, 3926, 3947, and 3948.
  • Move affected Red Hat build of Keycloak 26.2 deployments to unaffected 26.2.14 packages.
  • Move affected Red Hat build of Keycloak 26.4 deployments to unaffected 26.4.10 packages.
  • Review vendor guidance before relying on disabled SAML IdPs as a control.
  • Remove unneeded SAML broker configurations where business use has ended.

Validation and detection

  • Inventory Red Hat build of Keycloak package versions and operator bundle versions.
  • Identify realms with SAML identity providers configured, especially disabled providers.
  • Confirm deployed versions match unaffected package lines listed in Red Hat data.
  • Review authentication logs for broker logins involving disabled SAML IdP aliases.
  • Check Red Hat advisories for environment-specific update status and reboot requirements.
Prepared
Confidence
high
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-306: Credential and account abuse lookup

Authentication and credential weaknesses can make valid-account abuse and credential telemetry useful review starting points. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-2603 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.1 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
7Timeline events
2ADP providers
8Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.1CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N2.85.2redhat
8.1CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N2.85.2redhat-SADP

Vulnerability scoring details

Base CVSS 3.1 score

8.1High
CVSS 3.1 vector shape for CVE-2026-2603Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. ADP timelineredhat-SADP

    Reported to Red Hat.

  2. Source timelineredhat

    Reported to Red Hat.

  3. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  4. ADP timelineredhat-SADP

    Made public.

  5. Source timelineredhat

    Made public.

  6. CVE publishedCVE Program

    The CVE record was published.

  7. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPkeycloak: Keycloak: Unauthorized authentication via disabled SAML Identity Provider
other:Red Hat severity ratingcvssV3_1
  • 2026-02-16T21:15:53.373Z: Reported to Red Hat.
  • 2026-03-05T11:23:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Red HatRed Hat build of Keycloak 26.2rhbk/keycloak-operator-bundle, 26.2.14-1affected
Red HatRed Hat build of Keycloak 26.2rhbk/keycloak-rhel9, 26.2-16affected
Red HatRed Hat build of Keycloak 26.2rhbk/keycloak-rhel9-operator, 26.2-16affected
Red HatRed Hat build of Keycloak 26.2.14rhbk/keycloak-rhel9unaffected
Red HatRed Hat build of Keycloak 26.4rhbk/keycloak-operator-bundle, 26.4.10-1affected
Red HatRed Hat build of Keycloak 26.4rhbk/keycloak-rhel9, 26.4-12affected
Red HatRed Hat build of Keycloak 26.4rhbk/keycloak-rhel9-operator, 26.4-12affected
Red HatRed Hat build of Keycloak 26.4.10rhbk/keycloak-rhel9unaffected
Weakness

CWE details

CWE-306

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-306 · source CWE mapping

Missing Authentication for Critical Function

Missing Authentication for Critical Function represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs