CVE-2026-40230Public exploitNetwork attack vector

Stored XSS via falsely trusted Doc HTML

Published Apr 29, 2026 · Updated Apr 29, 2026

Stored cross-site scripting in Helpy 2.8.0 allows remote authenticated users to execute JavaScript in article visitors' browsers. DocsHelper#sanitize_doc_content labels RDiscount output as HTML-safe without sanitizing the attacker-controlled Doc body, bypassing Rails escaping. Execution requires an admin or agent editor to save the payload and a user to view the rendered article, exposing data and actions available to that browser session.

CVSS severity4.8
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Helpy 2.8.0 allows remote authenticated users to execute JavaScript in article visitors' browsers. DocsHelper#sanitize_doc_content labels RDiscount output as HTML-safe without sanitizing the attacker-controlled Doc body, bypassing Rails escaping. Execution requires an admin or agent editor to save the payload and a user to view the rendered article, exposing data and actions available to that browser session.

The record

CVE
CVE-2026-40230
Published
Apr 29, 2026
Updated
Apr 29, 2026
Vendor
Helpy
Product
Helpy
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 29, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=2.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Helpy · Helpyversion=2.8.0

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
4.8Fluid AttacksCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
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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