6.1 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:N/I:P/A:N
0.001 Low
EPSS
Percentile
49.6%
A self Cross-Site Scripting vulnerability exists in the @github/paste-markdown library. If the clipboard data contains the string <table>
, a div is dynamically created, and the clipboard content is copied into itsinnerHTML property without any sanitization, resulting in improper execution of JavaScript in the browser of the victim (the user who pasted the code). Users directed to copy text from a malicious website and paste it into pages that utilize this library are affected.
The following @github/paste-markdown code snippet is triggered when the user pastes something and the browser’s clipboard data contains an entry whose content-type is text/HTML.
function generateText(transfer: DataTransfer): string | undefined {
if (Array.from(transfer.types).indexOf('text/html') === -1) return
let html = transfer.getData('text/html')
if (!/<table/i.test(html)) return
html = html.replace(/<meta.*?>/, '')
const el = document.createElement('div')
el.innerHTML = html
const tables = el.querySelectorAll('table')
for (const table of tables) {
if (table.closest('[data-paste-markdown-skip]')) {
table.replaceWith(new Text(table.textContent || ''))
}
const formattedTable = tableMarkdown(table)
table.replaceWith(new Text(formattedTable))
}
return el.innerHTML
}
A security patch was released in version 0.3.4.
A Content Security Policy that prevents unsafe-inline
helps reduce the likelihood of this vulnerability being exploited in modern browsers.
CPE | Name | Operator | Version |
---|---|---|---|
@github/paste-markdown | lt | 0.3.4 |
github.com/advisories/GHSA-gpfj-4j6g-c4w9
github.com/github/paste-markdown/commit/32b7ea3f29ae8f256f9d19768387be42678ddf30
github.com/github/paste-markdown/releases/tag/v0.3.4
github.com/github/paste-markdown/security/advisories/GHSA-gpfj-4j6g-c4w9
nvd.nist.gov/vuln/detail/CVE-2021-37700
www.npmjs.com/package/@github/paste-markdown
6.1 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:N/I:P/A:N
0.001 Low
EPSS
Percentile
49.6%