Reflected XSS when importing CSV in OctoberCMS

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2020-5298: 0.91% estimated exploitation activity in the next 30 days; percentile 60.00 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact A user with the ability to use the import functionality of the ImportExportController behavior could be socially engineered by an attacker to upload a maliciously crafted CSV file which could result in a reflected XSS attack on the user in question Patches Issue has been patched in Build 466 (v1.0.466). Workarounds Apply https://github.com/octobercms/october/commit/cd0b6a791f995d86071a024464c1702efc50f46c to your installation manually if unable to upgrade to Build 466. References Reported by Sivanesh Ashok For more information If you have any questions or comments about this advisory: Email us at hello@octobercms.com Threat assessment: <img width="1100" alt="Screen Shot 2020-03-31 at 2 01 52 PM" src="https://user-images.githubusercontent.com/7253840/78070158-8f7ef580-7358-11ea-950c-226533f6a0a3.png"

Published by the source

3 Jun 2020, 21:58 UTC

Last modified by the source

27 Jan 2023, 05:00 UTC

Source last checked

26 Oct 2026, 13:59 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gg6x-xx78-448c

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# Patch Next advisory brief: CVE-2020-5298

Advisory: Reflected XSS when importing CSV in OctoberCMS
IDs: CVE-2020-5298, GHSA-gg6x-xx78-448c
Record: https://patchnext.com/advisories/cve-2020-5298 (revision 1, source checked 26 Oct 2026, 13:59 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 4.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: october/backend 1.0.466. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist october/backend: affected >= 1.0.319, < 1.0.466; fixed in 1.0.466

## Suggested inspection (read-only)
- Packagist october/backend: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on october/backend.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-gg6x-xx78-448c (GitHub-reviewed advisory GHSA-gg6x-xx78-448c lists affected ranges: Packagist october/backend >=1.0.319 <1.0.466)

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