CVE-2023-28756: ReDoS vulnerability in Time

We have released the time gem version 0.1.1 and 0.2.2 that has a security fix for a ReDoS vulnerability. This vulnerability has been assigned the CVE identifier CVE-2023-28756.


The Time parser mishandles invalid strings that have specific characters. It causes an increase in execution time for parsing strings to Time objects.

A ReDoS issue was discovered in the Time gem 0.1.0 and 0.2.1 and Time library of Ruby 2.7.7.

Recommended action

We recommend to update the time gem to version 0.2.2 or later. In order to ensure compatibility with bundled version in older Ruby series, you may update as follows instead:

  • For Ruby 3.0 users: Update to time 0.1.1
  • For Ruby 3.1/3.2 users: Update to time 0.2.2

You can use gem update time to update it. If you are using bundler, please add gem "time", ">= 0.2.2" to your Gemfile.

Unfortunately, time gem only works with Ruby 3.0 or later. If you are using Ruby 2.7, please use the latest version of Ruby.

Affected versions

  • Ruby 2.7.7 or lower
  • time gem 0.1.0
  • time gem 0.2.1


Thanks to ooooooo_q for discovering this issue.


  • Originally published at 2023-03-30 11:00:00 (UTC)