XSS in Github Paste-Markdown
CVE-2021-37700
@github/paste-markdown is an npm package for pasting markdown objects. A self Cross-Site Scripting vulnerability exists in the @github/paste-markdown before version 0.3.4. 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 (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. This is fixed in version 0.3.4. Refer the to the referenced GitHub Advisory for more details including an example exploit.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.017 (74.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.
Affected products
- Github Paste-markdown — versions < 0.3.4
- Paste-markdown_project Paste-markdown
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Third Party Advisory)
- security-advisories@github.com (Patch, Third Party Advisory, x_refsource_MISC)
- security-advisories@github.com (Third Party Advisory, x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2021-37700?
- CVE-2021-37700 is a medium-severity vulnerability in Github Paste-Markdown, classified under Cross-site Scripting. CVSS score: 6.5/10. Published 2021-08-12.
- How severe is CVE-2021-37700?
- Medium severity. CVSS v3 base score is 6.5 out of 10.