Skip to content

fix: escape HTML attribute values in markdown htmlTag to prevent stored XSS #240

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
sebastiondev wants to merge 1 commit into
base: main
Choose a base branch
from
+10 −1
Open

fix: escape HTML attribute values in markdown htmlTag to prevent stored XSS #240

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
11 changes: 10 additions & 1 deletion images/chromium-headful/client/src/components/markdown.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,15 @@ interface HTMLAttributes {

interface MarkdownState extends State {}

function escapeAttr(value: string): string {
return value
.replace(/&/g, '&')
.replace(/"/g, '"')
.replace(/</g, '&lt;')
.replace(/>/g, '&gt;')
.replace(/'/g, '&#x27;')
}

function htmlTag(
tagName: string,
content: string,
Expand All @@ -58,7 +67,7 @@ function htmlTag(
let attributeString = ''
for (const attr in attributes) {
if (Object.prototype.hasOwnProperty.call(attributes, attr) && attributes[attr]) {
attributeString += ` ${attr}="${attributes[attr]}"` // md.sanitizeText(attr)
attributeString += ` ${attr}="${escapeAttr(attributes[attr])}"`
}
}

Expand Down