# CVE-2026-23939: Path Traversal in Local File Store Backend

> Path traversal in hexpm's local storage backend allows attackers to read or modify files outside the intended directory in self-hosted deployments.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/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:** 26 Feb 2026
- **Updated:** 16 Sep 2026
- **Also known as:** EEF-CVE-2026-23939, GHSA-42mv-r64p-4869

## What is CVE-2026-23939?

CVE-2026-23939 is a medium-severity path traversal vulnerability in hexpm, published on 26 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in hexpm hexpm/hexpm ('Elixir.Hexpm.Store.Local' module) allows Relative Path Traversal. This vulnerability is associated with program files lib/hexpm/store/local.ex and program routines 'Elixir.Hexpm.Store.Local':get/3, 'Elixir.Hexpm.Store.Local':put/4, 'Elixir.Hexpm.Store.Local':delete/2, 'Elixir.Hexpm.Store.Local':delete_many/2.

This issue does NOT affect hex.pm the service. Only self-hosted deployments using the Local Storage backend are affected.

This issue affects hexpm: from 931ee0ed46fa89218e0400a4f6e6d15f96406050 before 5d2ccd2f14f45a63225a73fb5b1c937baf36fdc0.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-23939?

It affects 1 product.


Products: Hex Hexpm.

## How do I fix CVE-2026-23939?

No fix has been published for CVE-2026-23939 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-23939 being exploited?

There is no known exploitation of CVE-2026-23939 in the wild and no public exploit code.

## Other vulnerabilities in hexpm

- [CVE-2026-21622](https://insights.sbomify.com/CVE-2026-21622/): Password Reset Tokens Do Not Expire (critical 9.5)
- [CVE-2026-21618](https://insights.sbomify.com/CVE-2026-21618/): Cross-site scripting (XSS) in OAuth Device Authorization screen (high 8.5)
- [CVE-2026-23940](https://insights.sbomify.com/CVE-2026-23940/): Denial of Service via Oversized Package Upload (high 7.1)
- [CVE-2026-21621](https://insights.sbomify.com/CVE-2026-21621/): Improper Scope Enforcement in OAuth client_credentials Flow Allows Read-Only API Key to Escalate to Full Access (high 7.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23939 and fix it if it is affected.

What it is: CVE-2026-23939 is a medium-severity path traversal vulnerability in hexpm, published on 26 Feb 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-2026-23939 in the wild and no public exploit code.

Affected product: hexpm. 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-2026-23939/ (Markdown: https://insights.sbomify.com/CVE-2026-23939/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23939
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23939
- OSV: https://osv.dev/vulnerability/CVE-2026-23939

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23939/
Summaries are generated and may contain mistakes; the official description above is the record.