CVE-2026-24907Network attack vector

Privilege escalation via unsandboxed mail preview iframe

Published Apr 14, 2026 · Updated Apr 14, 2026

Stored XSS in October CMS before 3.7.14 and 4.0.0 through 4.1.9 allows remote authenticated users to execute script in a superuser's browser. The Event Log mail preview renders logged mail-template HTML in an iframe without sandbox restrictions, so embedded JavaScript runs in the viewer's backend browser context. Exploitation requires mail-template editing permission and a superuser to open the specific log entry, enabling actions with that viewer's privileges.

CVSS severity5.1
Medium
EPSS probability0.20%
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 October CMS before 3.7.14 and 4.0.0 through 4.1.9 allows remote authenticated users to execute script in a superuser's browser. The Event Log mail preview renders logged mail-template HTML in an iframe without sandbox restrictions, so embedded JavaScript runs in the viewer's backend browser context. Exploitation requires mail-template editing permission and a superuser to open the specific log entry, enabling actions with that viewer's privileges.

The record

CVE
CVE-2026-24907
Published
Apr 14, 2026
Updated
Apr 14, 2026
Vendor
October CMS
Product
October CMS
Classifications
CWE-79, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 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=< 3.7.14
  2. Affected versionversion=>= 4.0.0, < 4.1.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

October CMS · October CMSversion=< 3.7.14; version=>= 4.0.0, < 4.1.10

Published CVSS scores

5.1GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
5.4NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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