CVE-2026-21621

HIGH
2026-03-05 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
7.0
CVSS 4.0
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CVSS Vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
X

Lifecycle Timeline

2
Analysis Generated
Mar 12, 2026 - 22:06 vuln.today
CVE Published
Mar 05, 2026 - 20:16 nvd
HIGH 7.0

Tags

Privilege Escalation Authentication Bypass

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 routines 'Elixir.HexpmWeb.API.OAuthController':validate_scopes_against_key/2. This issue affects hexpm: from 71829cb6f6559bcceb1ef4e43a2fb8cdd3af654b before 71c127afebb7ed7cc637eb231b98feb802d62999.

Analysis

Hexpm's OAuth implementation fails to enforce read-only API key restrictions during token exchange, allowing an attacker with a victim's read-only API key and valid 2FA code to obtain a full-access API key with unrestricted permissions. This privilege escalation vulnerability affects users of the Hexpm package repository and enables unauthorized modification of packages and account settings. …

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Remediation

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.

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Priority Score

35
Low Medium High Critical
KEV: 0
EPSS: +0.0
CVSS: +35
POC: 0

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CVE-2026-21621 vulnerability details – vuln.today
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