Auth bypass in Cisa Malcolm
CVE-2026-90449
When a particular authentication mode is configured, the reverse proxy forwards requests for a bundled third-party administrative interface directly to that interface without applying the gateway's own authentication requirement first. All access control for this administrative interface, which manages the credential store used to gate every other service in the deployment, is delegated entirely to that third-party interface's own login mechanism. Any authentication weakness in that bundled interface would compromise the credential store protecting the rest of the deployment.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (9.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 9.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.002 · change: -0.003
Affected products
Weakness classification (CWE)
References
- raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2026/icsa-26… (vendor-advisory, government-resource)
- www.cisa.gov/news-events/ics-advisories/icsa-26-254-01
Frequently asked questions
- What is CVE-2026-90449?
- CVE-2026-90449 is a medium-severity vulnerability in Cisa Malcolm, classified under Missing Authentication for Critical Function. CVSS score: 6.5/10. Published 2026-09-11.
- How severe is CVE-2026-90449?
- Medium severity. CVSS v3 base score is 6.5 out of 10.