Summary
TZInfo relative path traversal vulnerability allows loading of arbitrary files
Impact
Affected versions
- 0.3.60 and earlier.
- 1.0.0 to 1.2.9 when used with the Ruby data source (tzinfo-data).
Vulnerability
With the Ruby data source (the tzinfo-data gem for tzinfo version 1.0.0 and later and built-in to earlier versions), time zones are defined in Ruby files. There is one file per time zone. Time zone files are loaded with require on demand. In the affected versions, TZInfo::Timezone.get fails to validate time zone identifiers correctly, allowing a new line character within the identifier. With Ruby version 1.9.3 and later, TZInfo::Timezone.get can be made to load unintended files with require, executing them within the Ruby process.
For example, with version 1.2.9, you can run the following to load a file with path /tmp/payload.rb:
TZInfo::Timezone.get("foo\n/../../../../../../../../../../../../../../../../tmp/payload")
The exact number of parent directory traversals needed will vary depending on the location of the tzinfo-data gem.
TZInfo versions 1.2.6 to 1.2.9 can be made to load files from outside of the Ruby load path. Versions up to and including 1.2.5 can only be made to load files from directories within the load path.
This could be exploited in, for example, a Ruby on Rails application using tzinfo version 1.2.9, that allows file uploads and has a time zone selector that accepts arbitrary time zone identifiers. The CVSS score and severity have been set on this basis.
Versions 2.0.0 and later are not vulnerable.
Patches
Versions 0.3.61 and 1.2.10 include fixes to correctly validate time zone identifiers (commit 9eddbb5c0e682736f61d0dd803b6031a5db9eadf for 0.3.x and commit 9905ca93abf7bf3e387bd592406e403cd18334c7 for 1.2.x).
Note that version 0.3.61 can still load arbitrary files from the Ruby load path if their name follows the rules for a valid time zone identifier and the file has a prefix of tzinfo/definition within a directory in the load path. For example if /tmp/upload was in the load path, then TZInfo::Timezone.get('foo') could load a file with path /tmp/upload/tzinfo/definition/foo.rb. Applications should ensure that untrusted files are not placed in a directory on the load path.
Workarounds
As a workaround, the time zone identifier can be validated before passing to TZInfo::Timezone.get by ensuring it matches the regular expression \A[A-Za-z0-9+\-_]+(?:\/[A-Za-z0-9+\-_]+)*\z.
For more information
If you have any questions or comments about this advisory:
- Open an issue in the tzinfo repository.
Impact
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2022-31163 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.3.61, 1.2.10); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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tzinfo to 0.3.61 or later; tzinfo to 1.2.10 or later
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Frequently Asked Questions
- What is CVE-2022-31163? CVE-2022-31163 is a high-severity path traversal vulnerability in tzinfo (rubygems), affecting versions < 0.3.61. It is fixed in 0.3.61, 1.2.10. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is CVE-2022-31163? CVE-2022-31163 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of tzinfo are affected by CVE-2022-31163? tzinfo (rubygems) versions < 0.3.61 is affected.
- Is there a fix for CVE-2022-31163? Yes. CVE-2022-31163 is fixed in 0.3.61, 1.2.10. Upgrade to this version or later.
- Is CVE-2022-31163 exploitable, and should I be worried? Whether CVE-2022-31163 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2022-31163 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2022-31163?
- Upgrade
tzinfoto 0.3.61 or later - Upgrade
tzinfoto 1.2.10 or later
- Upgrade