OctoberApplication · Octobercms

CVE-2026-24906

MEDIUM · 5.4 CVSS v3.1 Published 2026-04-14
Fix available
A fix is available. Upgrade to after 4.1.9 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
October is a Content Management System (CMS) and web platform. Versions prior to 3.7.14 and 4.1.10 contain a Stored Cross-Site Scripting (XSS) vulnerability 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. Exploitation could lead to privilege escalation if a superuser opens any RichEditor during routine content editing (e.g., editing a blog post), and requires authenticated backend access with editor settings permissions. This issue has been fixed in versions 3.7.14 and 4.1.10. To workaround this issue, restrict editor settings permissions to fully trusted administrators only

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

October CMS versions prior to 3.7.14 and 4.1.10 have a stored XSS vulnerability in the Backend Editor Settings. The Markup Classes fields (paragraph, inline, table styles) fail to sanitize input to valid CSS class names, allowing malicious values to be rendered unsanitized in Froala editor dropdown menus and executing JavaScript when users open a RichEditor.

MitigationUpdate October CMS to version 3.7.14 or 4.1.10 or later. As a compensating control, restrict editor settings permissions to only fully trusted administrators until the update is applied.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
OctoberApplication
Affected:<= 3.7.13>= 4.0.0, <= 4.1.9

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check October CMS version
    Log into the Backend and navigate to Settings > System > Updates, or check the version file (version.yaml or similar in the core installation directory)
    Affected if Version is 3.7.13 or lower, OR between 4.0.0 and 4.1.9 inclusive
  2. Locate Editor Settings in backend
    Navigate to Settings > Editor > Editor Settings in the October CMS backend panel
    Affected if You have access to these settings (typically administrators only)
  3. Inspect Markup Classes fields for unsanitized input
    Within Editor Settings, examine the fields: Paragraph Styles, Inline Styles, and Table Styles. Look for values containing quotes, angle brackets, or javascript: patterns
    Affected if Any of these fields contain class names with unescaped special characters like quotes (" or '), angle brackets (< or >), or suspicious patterns like "javascript:" or "onload="
  4. Verify database storage of editor config
    If database access is available, query the settings table (commonly backend_settings table) for records with keys containing 'markup_classes' or 'editor' and inspect the stored values
    Affected if Stored values in the database contain raw, unescaped HTML or JavaScript event handlers

You are affected if your October CMS version falls within 3.7.13 or below, or between 4.0.0 and 4.1.9, AND the Markup Classes fields in your Editor Settings contain unsanitized CSS class values with special characters or scriptable patterns.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 4.1.9
Interim mitigation

Update October CMS to version 3.7.14 or 4.1.10 or later. As a compensating control, restrict editor settings permissions to only fully trusted administrators until the update is applied.

Recommended fix High confidence

October CMS 3.7.14 (for 3.x branch) or 4.1.10 (for 4.x branch)

  1. 1. Backup your October CMS database and files before proceeding with any update.
  2. 2. If using October CMS 3.x branch (versions <= 3.7.13), upgrade to version 3.7.14.
  3. 3. If using October CMS 4.x branch (versions 4.0.0 - 4.1.9), upgrade to version 4.1.10.
  4. 4. Use the October CMS update mechanism (october:up command or backend updates page) to apply the upgrade.
  5. 5. Clear any caches after upgrade using the 'october:cache' clear command.
  6. 6. Verify the update was successful by checking the backend version number.
  7. 7. As an additional precaution, verify that Markup Classes fields in Backend Editor Settings now properly sanitize input.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in October Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-24906 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data