CVE-2026-27937Network attack vector

Script execution via unescaped DataTable query parameter

Published Apr 21, 2026 · Updated Apr 21, 2026

Reflected XSS in October CMS before 3.7.16 and 4.0.0 through 4.1.15 allows remote attackers to execute script via a crafted backend URL. The backend DataTable form widget renders a query parameter into its response without output escaping, creating a reflected injection point. Exploitation requires the customizable backend prefix to be known or guessed and an authenticated backend user to visit the crafted URL; it provides no stored persistence or direct access without that interaction.

CVSS severity3.1
Low
EPSS probability0.14%
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 October CMS before 3.7.16 and 4.0.0 through 4.1.15 allows remote attackers to execute script via a crafted backend URL. The backend DataTable form widget renders a query parameter into its response without output escaping, creating a reflected injection point. Exploitation requires the customizable backend prefix to be known or guessed and an authenticated backend user to visit the crafted URL; it provides no stored persistence or direct access without that interaction.

The record

CVE
CVE-2026-27937
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
October CMS
Product
October CMS
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 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=< 3.7.16
  2. Affected versionversion=>= 4.0.0, < 4.1.16

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

October CMS · October CMSversion=< 3.7.16; version=>= 4.0.0, < 4.1.16

Published CVSS scores

3.1GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001User Execution: Malicious Link

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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