Security readout for executives and security teams
Plain-English summary
CVE-2026-9801 is a denial-of-service flaw in Red Hat build of Keycloak. A highly privileged attacker, or someone controlling an upstream LDAP server, can send a malformed LDAP password policy response that crashes the Keycloak JVM. This can make all realms on the affected node unavailable.
Executive priority
Treat as a timely availability fix for identity infrastructure, not an emergency internet-wide compromise. Prioritize if Keycloak supports critical applications or shared realms, because one affected node crash can disrupt authentication service for users.
Technical view
Keycloak mishandles malformed LDAP password policy responses during password authentication, causing an OutOfMemoryError and JVM termination. The CVSS 3.1 score is 4.9 with network reachability, low attack complexity, high privileges required, no confidentiality or integrity impact, and high availability impact.
Likely exposure
Exposure is limited to affected Red Hat build of Keycloak 26.4 and 26.6 deployments using LDAP integration, especially where realm administrators can configure LDAP or where an upstream LDAP server could be compromised.
Exploitation context
Sources do not report active exploitation, and this CVE is not listed as KEV in the provided bundle. The attack requires high privileges or control of an upstream LDAP server, reducing likelihood but leaving meaningful outage risk.
Researcher notes
The key constraint is attacker position: high-privileged realm administrator or compromised/malicious LDAP server. Public sources describe impact and affected Red Hat builds but do not provide exploit details. Focus validation on version state, LDAP integration, administrative boundaries, and JVM crash indicators.
Mitigation direction
- Review the relevant Red Hat advisories for fixed packages and upgrade guidance.
- Prioritize affected Keycloak nodes integrated with LDAP identity stores.
- Restrict who can configure realm LDAP providers.
- Review trust and administrative control of upstream LDAP servers.
- Use vendor guidance if your exact package status is unclear.
Validation and detection
- Inventory Red Hat build of Keycloak versions and package releases.
- Compare installed packages against Red Hat advisory affected and unaffected status.
- Identify realms using LDAP federation or LDAP authentication flows.
- Check logs for OutOfMemoryError events and unexpected JVM restarts.
- Confirm patched nodes remain stable during normal LDAP authentication.
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 lookupCVE-2026-9801 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
- 4.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
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:L/PR:H/UI:N/S:U/C:N/I:N/A:H1.23.6redhatVulnerability scoring details
Base CVSS 3.1 score
4.9MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
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-2026-9801CVE reference, redhat · vdb-entry, x_refsource_REDHAT
- RHBZ#2482473CVE 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.