CVE-2026-21621
5.3 · MEDIUMOverview
CVE-2026-21621 is a medium-severity vulnerability affecting hex hexpm. It was published on March 5, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
Incorrect Authorization vulnerability in hexpm hexpm/hexpm ('Elixir.HexpmWeb.API.OAuthController' module) allows Privilege Escalation.
An API key created with read-only permissions (domain: "api", resource: "read") can be escalated to full write access under specific conditions.
When exchanging a read-only API key via the OAuth client_credentials grant, the resource qualifier is ignored. The resulting JWT receives the broad "api" scope instead of the expected "api:read" scope. This token is therefore treated as having full API access.
If an attacker is able to obtain a victim's read-only API key and a valid 2FA (TOTP) code for the victim account, they can use the incorrectly scoped JWT to create a new full-access API key with unrestricted API permissions that does not expire by default and can perform write operations such as publishing, retiring, or modifying packages.
This vulnerability is associated with program files lib/hexpm_web/controllers/api/oauth_controller.ex and program
Remediation
Check the references section for vendor advisories and patches from hex. Update hexpm to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| hex | hexpm | >= 2025-10-17, < 2026-03-05 | Affected |
Frequently Asked Questions
What is CVE-2026-21621?
CVE-2026-21621 is a medium-severity vulnerability affecting hex hexpm. It was published on March 5, 2026 and has a CVSS 3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2026-21621?
This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2026-21621?
Check the references section for vendor advisories and patches from hex. Update hexpm to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-21621?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-21621 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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