Medium severity · published Sep 11, 2026
CVE-2026-90452
Improper certificate validation in Malcolm
5.3
CVSS
0.1%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Adjacent
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 1% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
Malcolm · CISA
before v26.06.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-90452
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-90452
government-resource
https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2026/icsa-26-254-01.json
www.cisa.gov
https://www.cisa.gov/news-events/ics-advisories/icsa-26-254-01
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