CVE-2026-75542
Fix: hexpm/hexpm@bf0fb9dCVE-2026-75542 is a CWE-863 vulnerability. O3 Security confirms whether CVE-2026-75542 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
OAuth token exchange grants repository scopes for organizations the principal cannot access
Description
Summary
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.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-75542 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-75542 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-75542. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-75542 in your dependencies?
O3 detects CVE-2026-75542 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.