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OctoberApplication · Octobercms

CVE-2026-24907

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 Event Log mail preview feature. When viewing logged mail messages, HTML content was rendered in an iframe without proper sandboxing, allowing JavaScript execution in the viewer's browser context. This issue has been fixed in versions 3.7.14 and 4.1.10. If users are unable to update immediately, workarounds include restricting mail template editing permissions to fully trusted administrators only and restricting Event Log viewing permissions to minimize exposure.

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 contains a stored XSS vulnerability in the Event Log mail preview feature where HTML content from logged mail messages is rendered in an iframe without proper sandboxing. This allows stored malicious JavaScript to execute in the context of any user viewing the Event Log mail preview.

MitigationUpdate to October CMS versions 3.7.14 or 4.1.10 to receive the patch, or implement workarounds by restricting mail template editing permissions to trusted administrators only and limiting Event Log viewing permissions.

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 your October CMS version
    Locate the version file or composer.json in your October CMS installation root directory and identify the installed version number.
    Affected if The installed version is 3.7.13 or lower, or between 4.0.0 and 4.1.9 inclusive.
  2. Verify the Event Log module is in use
    Check your October CMS database for entries in the system_event_logs table, specifically looking for records with the mail template event type or logged mail messages.
    Affected if The Event Log contains logged mail messages that could have been crafted with malicious HTML content.
  3. Inspect mail template permissions
    Review user role and permission settings in the October CMS backend under Settings > Users > Roles to determine which user roles can edit mail templates.
    Affected if Non-administrator or untrusted users have permission to edit mail templates, allowing them to inject malicious JavaScript that gets logged.
  4. Inspect Event Log viewing permissions
    Review user role and permission settings in the October CMS backend under Settings > Users > Roles to determine which user roles can view the Event Log.
    Affected if Users with Event Log viewing permissions can access the mail preview feature where the XSS executes.

You are affected if your installed October CMS version falls within the vulnerable ranges AND the Event Log contains logged mail messages AND users with appropriate permissions can view the Event Log mail preview.

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 to October CMS versions 3.7.14 or 4.1.10 to receive the patch, or implement workarounds by restricting mail template editing permissions to trusted administrators only and limiting Event Log viewing permissions.

Recommended fix High confidence

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

  1. Verify your current October CMS version by checking the backend or version file
  2. Determine which major version branch you are on (3.x or 4.x)
  3. Back up your database and files before performing any upgrade
  4. If on version 3.x, upgrade to version 3.7.14
  5. If on version 4.x, upgrade to version 4.1.10
  6. Use the official October CMS update mechanism (october:up command or backend update feature)
  7. After upgrade, verify the Event Log mail preview renders safely without script execution
  8. Alternatively, as a config mitigation pending upgrade: restrict mail template editing permissions to only fully trusted administrators and limit Event Log viewing permissions to minimize exposure
Caveat Patch releases typically contain no breaking changes; minor version upgrades within the same major version should be safe

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

Fix this in October Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

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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-2026-24907 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