hexpm prior 2026-08-24 OAuth token endpoint oauth_controller.ex validate_scopes_against_key improper authorization

Summaryinfo

A vulnerability labeled as problematic has been found in hexpm. Affected by this issue is the function validate_scopes_against_key of the file lib/hexpm_web/controllers/api/oauth_controller.ex of the component OAuth token endpoint. The manipulation results in improper authorization. This vulnerability is cataloged as CVE-2026-75542. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, was found in hexpm. Affected is the function validate_scopes_against_key of the file lib/hexpm_web/controllers/api/oauth_controller.ex of the component OAuth token endpoint. The manipulation with an unknown input leads to a improper authorization vulnerability. CWE is classifying the issue as CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. This is going to have an impact on confidentiality. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-75542 since 08/18/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1548.002.

Upgrading to version 2026-08-24 eliminates this vulnerability.

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• hexpm

Website

• Product: https://github.com/hexpm/hexpm/

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