# CVE-2026-90451: Use of Default Credentials in Malcolm

> Attackers can forge authentication cookies for the packet-analysis component if the default secret in the example configuration is not regenerated during setup.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 11 Sep 2026
- **Updated:** 2 Oct 2026
- **Also known as:** GHSA-jf96-h34q-q5qw

## What is CVE-2026-90451?

CVE-2026-90451 is a high-severity vulnerability in CISA Malcolm, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An example environment-configuration file ships with a fixed, publicly-known secret value used to sign authentication cookies for a bundled packet-analysis component. A deployment that copies this example file into active configuration without running the setup routine that regenerates the value will use the known default, allowing an attacker aware of the default to forge valid authentication cookies for that component.

Weakness: CWE-1392 (Use of Default Credentials)

## Which versions are affected by CVE-2026-90451?


## How do I fix CVE-2026-90451?

No fix has been published for CVE-2026-90451 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-90451 being exploited?

There is no known exploitation of CVE-2026-90451 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90451 and fix it if it is affected.

What it is: CVE-2026-90451 is a high-severity vulnerability in CISA Malcolm, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-90451 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-2026-90451/ (Markdown: https://insights.sbomify.com/CVE-2026-90451/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90451
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90451
- OSV: https://osv.dev/vulnerability/CVE-2026-90451

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90451/
Summaries are generated and may contain mistakes; the official description above is the record.