vulnerability / NVI-00004368 / Revision 4
rhukster/dom-sanitizer: SVG tag allows CSS injection via unfiltered url() and @import directives
OSV carries this publisher advisory for rhukster/dom-sanitizer. This is an aggregated source copy; consult the original publisher and compare update dates.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
4.7 MEDIUM (3.1)
security-advisories@github.com severity; no combined Null risk score.
0.322%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.25238. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
rhukster/dom-sanitizer
source listedECOSYSTEM: introduced 0; fixed 1.0.10
### Summary DOMSanitizer::sanitize() allows elements in SVG content but never inspects their text content. CSS url() references and @import rules pass through unfiltered, causing the browser to issue HTTP requests to attacker-controlled hosts when the sanitized SVG is rendered. ### Details In src/DOMSanitizer.php, 'style' is listed in the SVG allowed-tag array (line 31). The sanitize() method (lines 111–133) removes disallowed tags and strips attributes matching the EXTERNAL_URL pattern — but text node content of elements is never examined. Because CSS rules live in text nodes, EXTERNAL_URL filtering never applies to them. Vulnerable code (src/DOMSanitizer.php, line 31): ```php 'svg' => ['style', 'path', 'rect', 'circle', ...], ``` The following payload survives sanitize() intact: ```svg * { background: url(https://attacker.example/collect); } ``` ### PoC ```php * { background: url(https://attacker.example/collect); }'; $sanitizer = new DOMSanitizer(DOMS
03 / Response
What to do next
- vendor patch
The original advisory lists fixed boundaries 1.0.10 for rhukster/dom-sanitizer. Confirm the publisher’s latest guidance.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-93vf-569f-22cq ↗
GitHub Advisory Database via OSV · vendor advisory
Observed . GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.
- CVE-2026-40301 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-40301 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 4 ·
Source facts changed; compare the preserved prior revision.
- Revision 3 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.