CVE-2026-27599Public exploitNetwork attack vector

Authenticated browser-script execution via stored mail-setting input

Published Mar 30, 2026 · Updated Mar 30, 2026

Stored cross-site scripting in CI4MS before 0.31.0.0 allows remote authenticated users to execute JavaScript through Mail Settings. The mail configuration fields persist untrusted values and insert them into HTML attributes without output encoding, allowing a payload to break out and run when the page renders. High-privilege access to Mail Settings is required, and execution is bounded to the actions and data available in the active browser session.

CVSS severity4.7
Medium
EPSS probability0.36%
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 CI4MS before 0.31.0.0 allows remote authenticated users to execute JavaScript through Mail Settings. The mail configuration fields persist untrusted values and insert them into HTML attributes without output encoding, allowing a payload to break out and run when the page renders. High-privilege access to Mail Settings is required, and execution is bounded to the actions and data available in the active browser session.

The record

CVE
CVE-2026-27599
Published
Mar 30, 2026
Updated
Mar 30, 2026
Vendor
Ci4MS
Product
CI4MS
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 30, 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

4.7GitHub, Inc. (CNA)CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L
7.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
9.1GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:H/UI:N/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 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 exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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