CVE-2026-90453: Open Redirect in Malcolm

Severity: low (CVSS 3.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-11 · updated 2026-10-02
Weakness: CWE-601

Description

A file-upload handler redirects the authenticated client's browser to a URL taken directly from that same request's Referer header, without validating it against the application's own origin. This allows an authenticated attacker to craft a request that causes another user's browser to be redirected to an arbitrary external destination after completing an upload.

Affected products

CISA Malcolm: before v26.06.0 — fixed in v26.06.0

How to fix

Upgrade to a fixed version: CISA Malcolm v26.06.0. Check the vendor advisory for mitigations.

References

https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/OT/white/2026/icsa-26-254-01.json
https://www.cisa.gov/news-events/ics-advisories/icsa-26-254-01

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