# CVE-2026-54584: mport trusts environment-controlled temporary directories in privileged metadata extraction

> An attacker controlling the environment can redirect privileged package metadata extraction to a malicious location, potentially leading to privilege escalation or code execution.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Sep 2026
- **Updated:** 25 Sep 2026
- **Also known as:** GHSA-4vv3-3h8r-q6mq

## What is CVE-2026-54584?

CVE-2026-54584 is a medium-severity path traversal vulnerability in MidnightBSD mport, published on 21 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

mport is the MidnightBSD Package Manager. mport before 2.7.8 used TMPDIR while extracting package metafiles, including when running as root or in setuid/setgid contexts. An attacker able to control the environment for a privileged mport invocation could redirect temporary metadata extraction to an attacker-controlled location. PR 123 ignores unsafe TMPDIR values in privileged contexts and rejects empty TMPDIR. This issue has been patched in version 2.7.8.

Weakness: CWE-73 (External Control of File Name or Path), CWE-377 (DEPRECATED: Insecure Temporary File)

## Which versions are affected by CVE-2026-54584?


## How do I fix CVE-2026-54584?

No fix has been published for CVE-2026-54584 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-54584 being exploited?

There is no known exploitation of CVE-2026-54584 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54584 and fix it if it is affected.

What it is: CVE-2026-54584 is a medium-severity path traversal vulnerability in MidnightBSD mport, published on 21 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-54584 in the wild and no public exploit code.

Affected product: MidnightBSD mport. 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-2026-54584/ (Markdown: https://insights.sbomify.com/CVE-2026-54584/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54584
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54584
- OSV: https://osv.dev/vulnerability/CVE-2026-54584

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54584/
Summaries are generated and may contain mistakes; the official description above is the record.