CVE-2026-25133Network attack vector

Stored XSS via SVG attribute-boundary bypass

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 run JavaScript via uploaded SVG files. The SVG sanitizer's regular expression misidentifies attribute boundaries, leaving crafted on-event attributes intact when Media Manager processes an upload. Exploitation requires backend media-upload permission and triggers only when a superuser views or embeds the stored SVG, enabling actions in that user's browser context.

CVSS severity4.8
Medium
EPSS probability0.22%
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 run JavaScript via uploaded SVG files. The SVG sanitizer's regular expression misidentifies attribute boundaries, leaving crafted on-event attributes intact when Media Manager processes an upload. Exploitation requires backend media-upload permission and triggers only when a superuser views or embeds the stored SVG, enabling actions in that user's browser context.

The record

CVE
CVE-2026-25133
Published
Apr 14, 2026
Updated
Apr 14, 2026
Vendor
October CMS
Product
October CMS
Classifications
CWE-79, T1204.002
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

4.8NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
4.8GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.002User Execution: Malicious File

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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