Improvement

October 31, 20211 Minute Read

Warning about bidirectional Unicode text

A warning is now displayed when a file's contents include bidirectional Unicode text. Such text can be interpreted or compiled differently than it appears in a user interface. For example, hidden, bidirectional Unicode characters can be used to swap segments of text in a file. This can cause code to appear one way and be interpreted or compiled another way.

image

This security issue is the topic of the Common Vulnerabilities and Exposures (CVE) publication: CVE-2021-42574. If your use of bidirectional Unicode characters is intentional and not malformed, you can ignore the warning.

To review a file for which this warning is displayed, open it in an editor that will display the hidden, bidirectional Unicode characters, like Visual Studio Code which highlights the characters by default. Then, verify that the characters are necessary and not disguising text that will be interpreted or compiled differently than it appears.

For more information, refer to Trojan Source: Invisible Source Code Vulnerabilities.

Subscribe to our developer newsletter

Discover tips, technical guides, and best practices in our biweekly newsletter just for devs.

By submitting, I agree to let GitHub and its affiliates use my information for personalized communications, targeted advertising, and campaign effectiveness. See the GitHub Privacy Statement for more details.

Warning about bidirectional Unicode text - GitHub Changelog