Control characters prepended before "javascript:" URLs pasted in the addressbar can cause the leading characters to be ignored and the pasted JavaScript to be executed instead of being blocked. This could be used in social engineering and self-cross-site-scripting (self-XSS) attacks where users are convinced to copy and paste text into the addressbar. This vulnerability affects Firefox < 57.

Related CVEs

CVE-2017-7839

Key Information

GHSA ID

GHSA-42vq-2prv-qxmf

Published

May 14, 2022 3:16 AM

Last Modified

May 14, 2022 3:16 AM

CVSS Score

5.0 /10

Primary Ecosystem

Unknown

Primary Package

Unknown

GitHub Reviewed

✗ No

Dataset

Last updated: September 12, 2025 6:34 AM

Data from GitHub Advisory Database. This information is provided for research and educational purposes.