vulnerability / NVI-00018276 / Revision 1
SillyTavern has a reflected XSS vulnerability in the CORS proxy middleware
GitHub lists this reviewed advisory for sillytavern. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
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.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
sillytavern
source listed<= 1.17.0
## Resolution Fixed in SillyTavern 1.18.0: a user-provided URL is no longer reflected in the HTTP response body. ## Overview - Vulnerability Type: XSS - Affected Location: `src/middleware/corsProxy.js:40` - Trigger Scenario: reflected XSS in CORS proxy error response ## Root Cause When `fetch(url)` throws, the code sends: `res.status(500).send('Error occurred while trying to proxy to: ' + url + ' ' + error)`. The `url` value is attacker-controlled (`req.params.url`) and is not HTML-escaped before rendering. ## Source-to-Sink Chain 1. Source (user-controlled input) - Entry point: `GET /proxy/:url(*)` 2. Data flow - Code analysis shows concrete propagation into this sink: - vulnerability title: `Reflected XSS in CORS proxy error response` - sink location reached by attacker-controlled input: `src/middleware/corsProxy.js:40` - The same sink behavior is confirmed by controlled execution observations. 3. Sink (dangerous operation) - Sink location: `src/middleware/corsProxy.js:40` - Vulnerable behavior: reflected XSS in CORS proxy error response ## Exploitation Preconditions 1. The attacker can inject controllable content into a rendered response. 2. The vulnerable rendering c
03 / Response
What to do next
- investigate
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-xc4x-2452-5gc9 ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.