# CVE-2026-75542: OAuth token exchange grants repository scopes for organizations the principal cannot access

> Attackers with repository-scoped API keys can access private packages from unauthorized organizations due to flawed OAuth token scope validation.

- **Severity:** High 8.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/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:** 24 Aug 2026
- **Updated:** 25 Aug 2026
- **Also known as:** EEF-CVE-2026-75542, GHSA-rfx8-w654-8cpr

## What is CVE-2026-75542?

CVE-2026-75542 is a high-severity missing authorization vulnerability in hexpm, published on 24 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Incorrect Authorization vulnerability in the OAuth token endpoint in hexpm hexpm allows an API key holding the repositories permission to read another organization's private packages.

When an API key is exchanged for a token through the OAuth client_credentials grant, validate_scopes_against_key/2 in lib/hexpm_web/controllers/api/oauth_controller.ex admits a requested scope whenever the key carries the repositories permission and the scope string begins with repository:. The organization name is never resolved against the principal, and expand_repositories_scope/3 only rewrites the literal repositories scope, so an explicit repository:<name> passes through untouched. Both CDN edges authorize repository access from the token claim without querying the database, so the minted token is read access to that organization's private packages until it expires.

This issue affects hex.pm: from 2025-10-18 before 2026-08-24.

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2026-75542?


## How do I fix CVE-2026-75542?

No fix has been published for CVE-2026-75542 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-75542 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-75542 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75542 and fix it if it is affected.

What it is: CVE-2026-75542 is a high-severity missing authorization vulnerability in hexpm, published on 24 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-75542 exists.

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-2026-75542/ (Markdown: https://insights.sbomify.com/CVE-2026-75542/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75542
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75542
- OSV: https://osv.dev/vulnerability/CVE-2026-75542

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75542/
Summaries are generated and may contain mistakes; the official description above is the record.