# CVE-2026-90452: Improper certificate validation in Malcolm

> Attackers can bypass certificate validation to impersonate the identity provider and issue forged authentication tokens in Malcolm deployments.

- **Severity:** Medium 6.0 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 Sep 2026
- **Updated:** 2 Oct 2026
- **Also known as:** GHSA-vfcm-4hjc-64rr

## What is CVE-2026-90452?

CVE-2026-90452 is a medium-severity vulnerability in CISA Malcolm, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-90452?


## How do I fix CVE-2026-90452?

No fix has been published for CVE-2026-90452 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-90452 being exploited?

There is no known exploitation of CVE-2026-90452 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90452 and fix it if it is affected.

What it is: CVE-2026-90452 is a medium-severity vulnerability in CISA Malcolm, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-90452 in the wild and no public exploit code.

Affected product: CISA Malcolm. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-90452/ (Markdown: https://insights.sbomify.com/CVE-2026-90452/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90452
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90452
- OSV: https://osv.dev/vulnerability/CVE-2026-90452

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90452/
Summaries are generated and may contain mistakes; the official description above is the record.