CVE-2026-34566Public exploitNetwork attack vector

Account takeover via unencoded stored page fields

Published Apr 1, 2026 · Updated Apr 1, 2026

Stored XSS in CI4MS Page Management before 0.31.0.0 allows remote authenticated users to execute JavaScript in other users' browsers. Page creation and editing fields store attacker-controlled scripts, and administrative page lists and public page views render those values without output encoding. Any role able to create or edit pages can trigger execution when another user views affected content, enabling account actions in that viewer's session.

CVSS severity9.1
Critical
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in CI4MS Page Management before 0.31.0.0 allows remote authenticated users to execute JavaScript in other users' browsers. Page creation and editing fields store attacker-controlled scripts, and administrative page lists and public page views render those values without output encoding. Any role able to create or edit pages can trigger execution when another user views affected content, enabling account actions in that viewer's session.

The record

CVE
CVE-2026-34566
Published
Apr 1, 2026
Updated
Apr 1, 2026
Vendor
Ci4MS
Product
CI4MS
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 1, 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=< 0.31.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Ci4MS · CI4MSversion=< 0.31.0.0

Published CVSS scores

9.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L
9.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

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')
T1059.007JavaScript/JScript

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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