CVE-2026-21618Public exploitNetwork attack vector

Reflected XSS via raw OAuth scope rendering

Published Jan 19, 2026 · Updated Jan 19, 2026

Reflected XSS in Six Colors AB Hex.pm before 2026-01-19 allows remote attackers to execute JavaScript via a crafted verification link. The render_grouped_scopes/3 routine interpolates attacker-controlled OAuth scope names and descriptions into HTML passed to raw(), bypassing output escaping. No authentication is required, but a victim must open the link; execution can read or alter data and actions within the device authorization flow.

CVSS severity8.5
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in Six Colors AB Hex.pm before 2026-01-19 allows remote attackers to execute JavaScript via a crafted verification link. The render_grouped_scopes/3 routine interpolates attacker-controlled OAuth scope names and descriptions into HTML passed to raw(), bypassing output escaping. No authentication is required, but a victim must open the link; execution can read or alter data and actions within the device authorization flow.

The record

CVE
CVE-2026-21618
Published
Jan 19, 2026
Updated
Jan 19, 2026
Vendor
Six Colors AB
Product
Hex.pm
Classifications
CWE-79, CAPEC-63, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 19, 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=2025-10-01 <2026-01-19
  2. Affected versionversion=617e44c71f1dd9043870205f371d375c5c4d886d <c692438684ead90c3bcbfb9ccf4e63c768c668a8
  3. Affected versionversion=pkg:github/hexpm/hexpm@617e44c71f1dd9043870205f371d375c5c4d886d <pkg:github/hexpm/hexpm@c692438684ead90c3bcbfb9ccf4e63c768c668a8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Six Colors AB · Hex.pmversion=2025-10-01 <2026-01-19; version=617e44c71f1dd9043870205f371d375c5c4d886d <c692438684ead90c3bcbfb9ccf4e63c768c668a8; version=pkg:github/hexpm/hexpm@617e44c71f1dd9043870205f371d375c5c4d886d <pkg:github/hexpm/hexpm@c692438684ead90c3bcbfb9ccf4e63c768c668a8

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
8.5Erlang Ecosystem FoundationCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:L/SI:L/SA: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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-63Cross-Site Scripting (XSS)
T1189Drive-by Compromise

Public exploit references

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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