CVE-2026-90452

Improper certificate validation in Malcolm

Published Sep 11, 2026 CVSS 4.0 · 6 Medium EPSS < 1% KEV · Not listed
Description
Requests from the reverse proxy to the identity-provider service for token discovery, introspection, and credential exchange do not verify the identity provider's server certificate. An attacker positioned on the network path between the proxy and the identity provider could impersonate the identity provider and issue forged authentication tokens accepted by the deployment.

Remediation

Vendor Solution

The latest version of Malcolm (September 2026 or later) fixes these vulnerabilities. Affected users are encouraged to update their instance of Malcolm to the latest version.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Title Improper certificate validation in Malcolm
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'}

Type Values Removed Values Added
Title Malcolm Reverse Proxy Fails to Verify Identity Provider Certificates
Type Values Removed Values Added
Title Malcolm Reverse Proxy Fails to Verify Identity Provider Certificates
Type Values Removed Values Added
Title Identity Provider TLS Certificate Verification Failure Enabling Forged Authentication Tokens
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Title Identity Provider TLS Certificate Verification Failure Enabling Forged Authentication Tokens
Type Values Removed Values Added
Title Unverified TLS Enables Identity Provider Impersonation and Token Forgery
Type Values Removed Values Added
First Time appeared Cisagov
Cisagov malcolm
Vendors & Products Cisagov
Cisagov malcolm
Type Values Removed Values Added
Title Unverified TLS Enables Identity Provider Impersonation and Token Forgery
Type Values Removed Values Added
Title Server Certificate Verification Failure in Malcolm Reverse Proxy
Type Values Removed Values Added
Title Server Certificate Verification Failure in Malcolm Reverse Proxy
Type Values Removed Values Added
Title Unverified TLS in Malcolm Reverse Proxy Allows Forged Authentication Tokens
Type Values Removed Values Added
Title Unverified TLS in Malcolm Reverse Proxy Allows Forged Authentication Tokens
Type Values Removed Values Added
Description Requests from the reverse proxy to the identity-provider service for token discovery, introspection, and credential exchange do not verify the identity provider's server certificate. An attacker positioned on the network path between the proxy and the identity provider could impersonate the identity provider and issue forged authentication tokens accepted by the deployment.
Weaknesses CWE-295
References
Metrics cvssV4_0

{'score': 6, 'vector': 'CVSS:4.0/AV:A/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
icscert
Published
Updated
Oct 2, 2026, 8:59 PM
Reserved
Sep 11, 2026, 9:00 PM
Status
Awaiting Analysis
Published
Sep 11, 2026, 10:16 PM
Modified
Oct 2, 2026, 9:16 PM