Security readout for executives and security teams
Plain-English summary
Keycloak may grant a low-privileged authenticated user the permissions of a client service account when an oversized subject_token JWT is handled incorrectly. The issue is serious for environments where service accounts have broad access, but the CVSS vector rates attack complexity high and no active exploitation is cited in the bundle.
Executive priority
Treat as a prioritized patching item for Keycloak environments, especially identity systems backing sensitive applications. It is not supported as actively exploited, but successful abuse could cross privilege boundaries and expose or alter protected resources.
Technical view
The TokenEndpoint silently drops a subject_token JWT exceeding a 4000-character limit and falls back to client credentials. In affected Red Hat build of Keycloak 26.4 and 26.6 packages, this can turn low-privileged authenticated access into service-account privilege escalation. CVSS is 6.8: network exploitable, low privileges required, no user interaction, high confidentiality and integrity impact.
Likely exposure
Exposure is limited to deployments using the affected Red Hat build of Keycloak 26.4 or 26.6 packages listed in the bundle. Risk depends heavily on whether clients use service accounts and what those service accounts can access.
Exploitation context
The source bundle does not cite public exploitation, proof-of-concept availability, or CISA KEV inclusion. Exploitation requires an authenticated low-privileged user and a specific oversized subject_token condition, which aligns with the high attack-complexity CVSS rating.
Researcher notes
Focus validation on TokenEndpoint behavior, subject_token size handling, and fallback to client credentials. The bundle names CWE-1284 and identifies affected Red Hat package streams, but does not provide detailed patch mechanics or exploit telemetry.
Mitigation direction
- Apply relevant Red Hat security advisories for affected Keycloak packages.
- Upgrade affected packages to vendor-designated unaffected builds where available.
- Review client service-account privileges and reduce excessive permissions.
- Monitor Red Hat CVE and errata pages for updated remediation guidance.
Validation and detection
- Inventory Red Hat build of Keycloak versions and package names.
- Compare installed packages against the affected and unaffected entries in the bundle.
- Identify clients with service accounts enabled and high-value permissions.
- Review TokenEndpoint authentication logs for abnormal oversized token activity.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-1284: 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 lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-9704 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
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.
SSVC decision data
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N1.65.2redhatVulnerability scoring details
Base CVSS 3.1 score
6.8MediumVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- Source timelineredhat
Reported to Red Hat.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- Source timelineredhat
Made public.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- RHSA-2026:25097CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:25098CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:30049CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- RHSA-2026:30050CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-9704CVE reference, redhat · vdb-entry, x_refsource_REDHAT
- RHBZ#2481877CVE reference, redhat · issue-tracking, x_refsource_REDHAT
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Validation of Specified Quantity in Input
Improper Validation of Specified Quantity in Input represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.