CVE-2026-24906: October/system Cross-Site Scripting Vulnerability
MODERATECVE-2026-24906 is a MODERATE (CVSS 5.4) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting October/system libraries in the Packagist ecosystem. The issue involves october cms has stored xss in backend editor markup classes. Remediation is available by upgrading affected packages to version 4.1.10, 3.7.14.
CVE-2026-24906 at a Glance
Security Impact
CVSS: 5.4
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N).
How to Fix CVE-2026-24906
To remediate this vulnerability, upgrade all affected October/system dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade october/system to 4.1.10Upgrade october/system to 3.7.14Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for october/systemHow to Check if You Are Affected
To determine whether your application is affected by CVE-2026-24906, inspect your project dependencies for October/system:
inspect dependencies for october/systemAnalyze the terminal output to locate any version of October/system in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.1.10), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In October/system, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-24906 Affected October/system Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
october/system
|
Packagist |
≥ 4.0.0
< 4.1.10
|
4.1.10
|
|
october/system
|
Packagist |
< 3.7.14
|
3.7.14
|
References
Frequently Asked Questions
What is CVE-2026-24906?
Which October/system versions are affected?
What version fixes CVE-2026-24906?
Is october/system affected?
What is the CVSS score of CVE-2026-24906?
What CWE is associated with CVE-2026-24906?
How can I check Packagist dependencies for CVE-2026-24906?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-6qmh-j78v-ffp7",
"modified" : "2026-04-24T21:06:24Z",
"published" : "2026-04-14T20:02:31Z",
"aliases" : [ "CVE-2026-24906" ],
"summary" : "October CMS has Stored XSS in Backend Editor Markup Classes",
"details" : "A stored cross-site scripting (XSS) vulnerability was identified in the Backend Editor Settings. The Markup Classes fields (used for paragraph styles, inline styles, table styles, etc.) did not sanitize input to valid CSS class name characters. Malicious values were rendered unsanitized in Froala editor dropdown menus, allowing JavaScript execution when any user opened a RichEditor.\n\n### Impact\n- Stored XSS via editor settings rendered in RichEditor dropdowns\n- Could allow privilege escalation if a superuser opens any RichEditor (e.g., editing a blog post)\n- Requires authenticated backend access with editor settings permissions\n- Triggers on routine content editing operations\n\n### Patches\nThe vulnerability has been patched in v3.7.14 and v4.1.10. All users are encouraged to upgrade to the latest patched version.\n\n### Workarounds\nIf upgrading immediately is not possible:\n- Restrict editor settings permissions to fully trusted administrators only\n\n### References\n- Reported by [Chris Alupului](https://github.com/neosprings)",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"
}, {
"type" : "CVSS_V4",
"score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Packagist",
"name" : "october/system"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.0.0"
}, {
"fixed" : "4.1.10"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.1.9"
}
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "october/system"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "3.7.14"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 3.7.13"
}
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/octobercms/october/security/advisories/GHSA-6qmh-j78v-ffp7"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-24906"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/octobercms/october"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-79" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-04-14T20:02:31Z",
"nvd_published_at" : "2026-04-14T18:16:45Z"
}
}