high CVSS 8.8

CVE-2025-66474·Python vulnerability

XWiki Rendering is a generic rendering system that converts textual input in a given syntax (wiki syntax, HTML, etc) into another syntax (XHTML, etc). Versions 16.10.9 and below, 17.0.0-rc-1 through 17.4.2 and 17.5.0-rc-1 through 17.5.0 have insufficient protection against {{/html}} injection, which attackers can exploit through RCE. Any user who can edit their own profile or any other document can execute arbitrary script macros, including Groovy and Python macros, which enable remote code execution as well as unrestricted read and write access to all wiki contents. This issue is fixed in versions 16.10.10, 17.4.3 and 17.6.0-rc-1.

Severity
high
Software
Python
Fixed in
17.4.3
Published
2025-12-10

Affected versions

From: 17.0.0

Until: 17.4.3

Fixed in: 17.4.3

How to fix this CVE

Update XWiki Rendering to version 17.4.3 or later to patch the HTML injection vulnerability that allows arbitrary code execution through profile and document editing. Organizations running versions 17.0.0 through 17.4.2 should prioritize this update, as any authenticated user can exploit the {{/html}} injection flaw to execute Groovy and Python macros with full wiki access.

sudo dnf update python3

Defensia detects this vulnerability

What an exploitation attempt looks like

Sample log line indicative of exploitation attempts:

POST /bin/edit/.*\bprofile\b|POST /bin/save/.*content.*\b{{/html}}\b|groovy\.execute|python\.eval

WAF mitigation (if patching is not yet possible)

Add this rule to your WAF to block exploitation attempts while you schedule the patch. 

Block HTTP POST requests containing {{/html}}, {{groovy}}, or {{python}} patterns in request bodies targeting /bin/edit, /bin/save, and profile endpoints; enforce strict input validation on wiki macro syntax before rendering.

How to check if you are affected

  1. Step 1: Run `python3 --version` to verify your installed Python version; this CVE affects XWiki Rendering on systems where Python is available for macro execution.
  2. Step 2: Check your XWiki installation with `grep -r 'version' /path/to/xwiki/WEB-INF/` or review the Administration panel to confirm if you're running XWiki Rendering 17.0.0–17.4.2.
  3. Step 3: Search application logs for patterns like `{{/html}}`, `groovy`, or `python` in profile edits and document modifications using `grep -i '{{/html\|groovy\|python' /var/log/xwiki/application.log | head -50`.
  4. Step 4: Verify the patch by checking the XWiki version in Administration > System Information; it should display 17.4.3 or later for the vulnerability to be resolved.

FAQ

What is CVE-2025-66474?

This vulnerability exploits insufficient input sanitization in XWiki Rendering's HTML handling, allowing authenticated users to inject {{/html}} tags that bypass security filters and execute arbitrary Groovy or Python macros with full system privileges.

Is CVE-2025-66474 being actively exploited?

No, CVE-2025-66474 is not currently listed on CISA's Known Exploited Vulnerabilities catalog, and no public exploits are widely available. However, the low barrier to entry (any authenticated user) makes proactive patching essential.

What versions of Python are affected by CVE-2025-66474?

XWiki Rendering versions 16.10.9 and below, 17.0.0 through 17.4.2, and 17.5.0-rc-1 through 17.5.0 are vulnerable; the fix is available in versions 16.10.10, 17.4.3, and 17.6.0-rc-1 and later.

How do I check if my server is vulnerable to CVE-2025-66474?

Run `curl http://your-xwiki-server/bin/view/Main/WebHome` and check the page source or admin console for the XWiki version number; if it falls between 17.0.0 and 17.4.2, your installation is vulnerable.

Does Defensia detect CVE-2025-66474?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Python is installed on a monitored server, CVE-2025-66474 will appear in your dashboard with remediation steps.

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References

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