LiveActive security incident?Get immediate response
CVE Record

CVE-2025-12390: Org.keycloak.protocol.oidc.endpoints.logoutendpoint: offline session takeover due to reused authentication session id

A flaw was found in Keycloak. In Keycloak where a user can accidentally get access to another user's session if both use the same device and browser. This happens because Keycloak sometimes reuses session identifiers and doesn’t clean up properly during logout when browser cookies are missing. As a result, one user may receive tokens that belong to another user.

MediumCVSS 6Not KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Keycloak may give one user another user’s tokens when people share the same device and browser. The issue involves reused session identifiers and incomplete logout cleanup when browser cookies are missing. Successful abuse could expose accounts and allow unauthorized actions, but the required conditions make broad remote exploitation unlikely.

Executive priority

Prioritize remediation for kiosks, shared workstations, support terminals, and other multi-user browser environments. Treat ordinary single-user endpoints as lower urgency, while still updating through normal vulnerability-management timelines. Account-token crossover creates meaningful confidentiality and integrity risk even though exploitation conditions are restrictive.

Technical view

This CWE-384 session-fixation flaw affects Keycloak logout and offline-session handling. Reuse of an authentication-session identifier, combined with missing browser cookies and insufficient logout cleanup, can associate a later user with another user’s tokens. CVSS 3.1 is 6.0: local access, high complexity, low privileges, user interaction, and high confidentiality and integrity impact.

Likely exposure

Exposure is most plausible on listed affected Red Hat build of Keycloak 26.2 and 26.4 packages where multiple users share a browser profile or device. The bundle lists 26.2.11 and 26.4.4 as unaffected, but package-level entries differ; verify exact installed package builds against Red Hat advisories.

Exploitation context

The source bundle does not report active exploitation, and the CVE is not listed as KEV. Exploitation requires a constrained shared-device/browser scenario, missing cookies during logout, user interaction, local access, low privileges, and high complexity. Evidence of practical exploitation prevalence is not provided.

Researcher notes

The central condition is authentication-session identifier reuse during logout when expected browser cookies are absent, potentially exposing offline-session tokens across users. Package-level affected entries and product-level unaffected entries require careful build mapping. The supplied evidence does not establish a universal upstream Keycloak affected range, exploit availability, or observed attacks.

Mitigation direction

  • Inventory Keycloak products, versions, package names, and exact installed builds.
  • Compare installed builds with the affected and unaffected entries in Red Hat advisories.
  • Apply the applicable Red Hat security advisory updates using supported deployment procedures.
  • Review vendor guidance before implementing compensating controls or assuming upstream version equivalence.
  • Until updated, reduce shared-browser use and require separate browser profiles for different users.

Validation and detection

  • Confirm deployed package builds no longer match affected entries in the applicable advisory.
  • Verify the deployment reports an unaffected or vendor-corrected build after updating.
  • Test logout and subsequent login isolation using separate test accounts in a controlled environment.
  • Confirm tokens issued after logout belong only to the newly authenticated test account.
  • Review shared-device policies and identify environments where users reuse the same browser profile.
Prepared
Confidence
medium
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 · low confidence lookup

CWE-384: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. 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-2025-12390 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
Medium
CVSS
6 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/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.

1CVSS vectors
5Timeline events
1ADP providers
8Source links

SSVC decision data

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

CVSS vector scores

1 official score

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
6CVSS 3.1MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N0.85.2redhat

Vulnerability scoring details

Base CVSS 3.1 score

6Medium
CVSS 3.1 vector shape for CVE-2025-12390Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/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. Source timelineredhat

    Made public.

  2. Source timelineredhat

    Reported to Red Hat.

  3. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

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

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Keycloakkeycloakkeycloak, 0unaffected
Red HatRed Hat build of Keycloak 26.2rhbk/keycloak-operator-bundle, 26.2.11-1affected
Red HatRed Hat build of Keycloak 26.2rhbk/keycloak-rhel9, 26.2-12affected
Red HatRed Hat build of Keycloak 26.2rhbk/keycloak-rhel9-operator, 26.2-12affected
Red HatRed Hat build of Keycloak 26.2.11See advisoryunaffected
Red HatRed Hat build of Keycloak 26.4rhbk/keycloak-operator-bundle, 26.4.4-1affected
Red HatRed Hat build of Keycloak 26.4rhbk/keycloak-rhel9, 26.4-3affected
Red HatRed Hat build of Keycloak 26.4rhbk/keycloak-rhel9-operator, 26.4-3affected
Red HatRed Hat build of Keycloak 26.4.4keycloakunaffected
Weakness

CWE details

CWE-384

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