Silverstripe uses TinyMCE which allows svg files linked in object tags

Exploitation

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

CVSS 4.0

5.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N · score source

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact TinyMCE v6 has a configuration value convertunsafeembeds set to false which allows svg files containing javascript to be used in <object or <embed tags, which can be used as a vector for XSS attacks. Note that <embed tags are not allowed by default. After patching the default value of convertunsafeembeds will be set to true. This means that <object tags will be converted to iframes instead the next time the page is saved, which may break any pages that rely upon previously saved <object tags. Developers can override this configuration if desired to revert to the original behaviour. We reviewed the potential impact of this vulnerability within the context of Silverstripe CMS. We concluded this is a medium impact vulnerability given how TinyMCE is used by Silverstripe CMS. References: - https://www.silverstripe.org/download/security-releases/ss-2024-001 - https://github.com/advisories/GHSA-5359-pvf2-pw78

Published by the source

17 Jul 2024, 16:00 UTC

Last modified by the source

1 Aug 2024, 05:06 UTC

Source last checked

26 Oct 2026, 14:25 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-52cw-pvq9-9m5v

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# Patch Next advisory brief: GHSA-52cw-pvq9-9m5v

Advisory: Silverstripe uses TinyMCE which allows svg files linked in object tags
IDs: GHSA-52cw-pvq9-9m5v
Record: https://patchnext.com/advisories/ghsa-52cw-pvq9-9m5v (revision 1, source checked 26 Oct 2026, 14:25 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: silverstripe/framework 5.2.16. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist silverstripe/framework: affected < 5.2.16; fixed in 5.2.16

## Suggested inspection (read-only)
- Packagist silverstripe/framework: 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 silverstripe/framework.
- 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-52cw-pvq9-9m5v (GitHub-reviewed advisory GHSA-52cw-pvq9-9m5v lists affected ranges: Packagist silverstripe/framework >=0 <5.2.16)

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