Cross-site scripting (XSS) in the dynamic file uploads

Exploitation

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

CVSS

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

EPSS

• CVE-2023-51447: 0.49% estimated exploitation activity in the next 30 days; percentile 42.40 (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 The dynamic file upload feature is subject to potential XSS attach in case the attacker manages to modify the file names of the records being uploaded to the server. This appears in sections where the user controls the file upload dialogs themselves and has the technical knowledge to change the file names through the dynamic upload endpoint. Therefore I believe it would require the attacker to control the whole session of the particular user but in any case, this needs to be fixed. Successful exploit of this vulneratibility would require the user to have successfully uploaded a file blob to the server with a malicious file name and then have the possibility to direct the other user to the edit page of the record where the attachment is attached. The users are able to craft the direct upload requests themselves controlling the file name that gets stored to the database as shown here:…

Published by the source

20 Feb 2024, 23:42 UTC

Last modified by the source

20 Mar 2026, 05:03 UTC

Source last checked

26 Oct 2026, 15:51 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-9w99-78rj-hmxq

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# Patch Next advisory brief: CVE-2023-51447

Advisory: Cross-site scripting (XSS) in the dynamic file uploads
IDs: CVE-2023-51447, GHSA-9w99-78rj-hmxq
Record: https://patchnext.com/advisories/cve-2023-51447 (revision 1, source checked 26 Oct 2026, 15:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: decidim 0.27.5; decidim-core 0.27.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems decidim: affected >= 0.27.0, < 0.27.5; fixed in 0.27.5
- RubyGems decidim-core: affected >= 0.27.0, < 0.27.5; fixed in 0.27.5

## Suggested inspection (read-only)
- RubyGems decidim: check the installed version with your package manager.
- RubyGems decidim-core: 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 decidim, decidim-core.
- 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-9w99-78rj-hmxq (GitHub-reviewed advisory GHSA-9w99-78rj-hmxq lists affected ranges: RubyGems decidim >=0.27.0 =0.27.0 <0.27.5)

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