CVE-2026-21621Network attack vector

API privilege escalation via ignored resource qualifier

Published Mar 5, 2026 · Updated Mar 5, 2026

Incorrect authorization in Hex.pm before 2026-03-05 allows remote authenticated users to obtain full API write access through OAuth. validate_scopes_against_key/2 treats every api-domain permission as the broad api scope, ignoring the read resource qualifier during client_credentials exchange. Exploitation requires a victim's read-only API key and valid TOTP code, after which an unrestricted API key can publish, retire, or modify packages.

CVSS severity7.0
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Hex.pm before 2026-03-05 allows remote authenticated users to obtain full API write access through OAuth. validate_scopes_against_key/2 treats every api-domain permission as the broad api scope, ignoring the read resource qualifier during client_credentials exchange. Exploitation requires a victim's read-only API key and valid TOTP code, after which an unrestricted API key can publish, retire, or modify packages.

The record

CVE
CVE-2026-21621
Published
Mar 5, 2026
Updated
Mar 5, 2026
Vendor
Six Colors AB
Product
Hex.pm
Classifications
CWE-863, T1098
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2025-08-18 <2026-03-05
  2. Affected versionversion=71829cb6f6559bcceb1ef4e43a2fb8cdd3af654b <71c127afebb7ed7cc637eb231b98feb802d62999
  3. Affected versionversion=pkg:github/hexpm/hexpm@71829cb6f6559bcceb1ef4e43a2fb8cdd3af654b <pkg:github/hexpm/hexpm@71c127afebb7ed7cc637eb231b98feb802d62999

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Six Colors AB · Hex.pmversion=2025-08-18 <2026-03-05; version=71829cb6f6559bcceb1ef4e43a2fb8cdd3af654b <71c127afebb7ed7cc637eb231b98feb802d62999; version=pkg:github/hexpm/hexpm@71829cb6f6559bcceb1ef4e43a2fb8cdd3af654b <pkg:github/hexpm/hexpm@71c127afebb7ed7cc637eb231b98feb802d62999

Published CVSS scores

7.1GitHub Security AdvisoryCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:L
7.0EEFCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:H/SA:N
5.3NVDCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1098Account Manipulation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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