# CVE-2026-117533: REDAXO stored cross-site scripting in mediapool SVG uploads

Source: https://junglewise.ai/threats/cve-2026-117533-redaxo-from-5-18-0-before-5-21-4-contains-a-stored-cross-site  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-27. Updated: 2026-10-27  
License: CC BY 4.0 with a link back

CVE-2026-117533 · Severity: medium · CVSS 4.4 · Published 2026-10-27

REDAXO is a content management system that manages website content and media assets. The mediapool component uploads and serves image files, including SVG images. A vulnerability allows authenticated users with upload permissions to place malicious scripts inside SVG files that execute in other users' browsers when they view the media, potentially compromising backend sessions and allowing attackers to control the website.

Technologies: [REDAXO](https://junglewise.ai/threats/technologies/redaxo). Vendors: [REDAXO](https://junglewise.ai/threats/vendors/redaxo).

## Quick answers

**Is CVE-2026-117533 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-117533 being exploited in the wild.

**How severe is CVE-2026-117533?** Medium severity, with a CVSS score of 4.4, published 27 October 2026.

**Which products and versions are affected?** REDAXO 5.18.0 to 5.21.3.

**Is there a fix for CVE-2026-117533?** Yes: fixed in 5.21.4. Until then: Restrict mediapool upload and edit permissions to trusted users only. Alternatively, block SVG uploads entirely by adding 'svg' to the mediapool's blocked_extensions list. At the web server level (e.g., Apache .htaccess), restrict script execution for SVG files in the /media/ directory using Content-Security-Policy: sandbox and X-Content-Type-Options: nosniff headers. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-117533 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-117533?** Check whether you run REDAXO at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 5.21.4

Restrict mediapool upload and edit permissions to trusted users only. Alternatively, block SVG uploads entirely by adding 'svg' to the mediapool's blocked_extensions list. At the web server level (e.g., Apache .htaccess), restrict script execution for SVG files in the /media/ directory using Content-Security-Policy: sandbox and X-Content-Type-Options: nosniff headers.

## Technical details

The vulnerability is a stored cross-site scripting issue in the mediapool's SVG handling. SVG files are moved into the public /media/ folder via rename() before the sanitizer runs, creating a race condition window where unmodified, script-laden uploads are publicly accessible. An attacker with mediapool upload or edit rights can exploit this by either racing requests against the sanitizer (which takes milliseconds to complete) or exhausting server resources (memory_limit or max_execution_time) to prevent sanitization from finishing, leaving the malicious SVG permanently exposed and executable in victims' browser contexts.

## Affected products

- REDAXO REDAXO 5.18.0 to 5.21.3

## Timeline

- 2026-08-03: disclosed
- 2026-10-27: advisory
- 2026-10-27: patched

## References

- [https://github.com/redaxo/core/security/advisories/GHSA-2p3g-jr7p-qwwx](https://github.com/redaxo/core/security/advisories/GHSA-2p3g-jr7p-qwwx)
- [https://www.vulncheck.com/advisories/redaxo-5.18.0-before-5.21.4-stored-xss-via-unsanitized-mediapool-svg-uploads](https://www.vulncheck.com/advisories/redaxo-5.18.0-before-5.21.4-stored-xss-via-unsanitized-mediapool-svg-uploads)

## Related threats

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- [REDAXO CSRF token bypass in user administration](https://junglewise.ai/threats/cve-2026-117536-redaxo-before-5-21-3-contains-a-cross-site-request-forgery)
- [REDAXO reflected cross-site scripting in media pool](https://junglewise.ai/threats/cve-2026-117535-redaxo-before-5-21-3-contains-a-reflected-cross-site-scripting)
- [REDAXO cross-site request forgery in article history plugin](https://junglewise.ai/threats/cve-2026-117534-redaxo-before-5-21-3-contains-a-cross-site-request-forgery)
- [REDAXO stored cross-site scripting in media and link widgets](https://junglewise.ai/threats/cve-2026-116900-redaxo-before-5-21-4-contains-a-stored-cross-site-scripting)