What’s Vulnerable › Vulnerabilities

CVE-2026-90447: Authentication Bypass by Spoofing in Malcolm

• Severity: medium (CVSS 6.5 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-290

Description

A routing rule selects between two different authentication mechanisms for the same downstream service based on the value of a client-supplied request header, rather than on any property the client cannot control. An authenticated user in possession of a shared service credential can set this header to route around the primary role-based authorization check and reach the alternate path's fixed, elevated role instead. This allows a low-privileged authenticated attacker who knows the shared credential to perform actions reserved for a higher-privileged role.

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

Get alerted when CVE-2026-90447 or the next vulnerability affects your stack