Security readout for executives and security teams
Plain-English summary
Keycloak 11.0.3 and 12.0.0 could accept an expired certificate during direct-grant authentication. If an attacker already has the needed privileges and an expired certificate, they may gain improper authentication results affecting confidentiality and integrity.
Executive priority
Treat as a moderate identity-platform issue. Prioritize remediation if affected Keycloak versions protect sensitive applications, are internet-facing, or rely on certificate authentication in direct-grant flows.
Technical view
The flaw is missing timestamp validation in Keycloak's direct-grant authenticator. The CVSS 3.1 vector is network-reachable, low complexity, requires low privileges, no user interaction, unchanged scope, with low confidentiality and integrity impact and no availability impact.
Likely exposure
Exposure is limited to Keycloak deployments running versions 11.0.3 or 12.0.0, especially where direct-grant authentication and certificate-based flows are enabled or reachable.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation evidence. The CVSS vector indicates exploitation requires network access and low privileges, but no user interaction.
Researcher notes
Evidence is concise and does not include exploit details or a named fixed version in the supplied bundle. Focus validation on version presence, direct-grant authenticator exposure, and certificate expiration enforcement.
Mitigation direction
- Inventory Keycloak deployments and identify versions 11.0.3 or 12.0.0.
- Check Red Hat or Keycloak guidance for fixed supported builds and update accordingly.
- Restrict direct-grant authentication where it is not required.
- Remove expired certificates from trusted authentication paths where operationally safe.
- Monitor identity logs for authentication using expired certificates.
Validation and detection
- Confirm affected Keycloak versions are not deployed in production.
- Verify whether direct-grant authentication is enabled and externally reachable.
- Review certificate authentication settings for missing expiration enforcement.
- Confirm patched systems reject expired certificates in controlled testing.
- Check identity logs for suspicious direct-grant authentication outcomes.
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
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ATT&CK lookup starting points
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CWE-20: Exact CWE lookup
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Open ATT&CK lookupCVE-2020-35509 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
- 5.4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/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.
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:L/UI:N/S:U/C:L/I:L/A:N2.82.5Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.4MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://access.redhat.com/security/cve/cve-2020-35509CVE reference · x_refsource_MISC
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 Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.