PT-2021-21820 · Github · @Github/Paste-Markdown

Bananabr · Published 2021-08-12 · Updated 2021-08-23 · CVE-2021-37700

Positive Technologies (AI Summary)

CVSS v3.1

6.5

Medium

Base vector

AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Name of the Vulnerable Software and Affected Versions @github/paste-markdown versions prior to 0.3.4

Description A self Cross-Site Scripting issue 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 its innerHTML property without any sanitization, resulting in improper execution of JavaScript in the browser of the victim. Users directed to copy text from a malicious website and paste it into pages that utilize this library are affected.

Recommendations For versions prior to 0.3.4, update to version 0.3.4 to resolve the issue. As a temporary workaround, consider implementing a Content Security Policy that prevents unsafe-inline to reduce the likelihood of this issue being exploited in modern browsers.

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2021-37700

GHSA-GPFJ-4J6G-C4W9

Affected Products

@Github/Paste-Markdown

References · 10

• 🔥 https://github.com/github/paste-markdown/security/advisories/GHSA-gpfj-4j6g-c4w9 · Exploit
• https://github.com/github/paste-markdown/commit/32b7ea3f29ae8f256f9d19768387be42678ddf30 · Patch
• https://osv.dev/vulnerability/CVE-2021-37700 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-37700 · Security Note
• https://osv.dev/vulnerability/GHSA-gpfj-4j6g-c4w9 · Vendor Advisory
• https://github.com/github/paste-markdown/releases/tag/v0.3.4 · Note
• https://github.com/github/paste-markdown · Note
• https://npmjs.com/package/%40github/paste-markdown · Note
• https://npmjs.com/package/@github/paste-markdown · Note
• https://t.me/cibsecurity/27271 · Telegram Post