Summary
Incorrect Default Permissions in log4js
Impact
Default file permissions for log files created by the file, fileSync and dateFile appenders are world-readable (in unix). This could cause problems if log files contain sensitive information. This would affect any users that have not supplied their own permissions for the files via the mode parameter in the config.
Patches
Fixed by:
- https://github.com/log4js-node/log4js-node/pull/1141
- https://github.com/log4js-node/streamroller/pull/87
Released to NPM in [email protected]
Workarounds
Every version of log4js published allows passing the mode parameter to the configuration of file appenders, see the documentation for details.
References
Thanks to ranjit-git for raising the issue, and to @lamweili for fixing the problem.
For more information
If you have any questions or comments about this advisory:
- Open an issue in logj4s-node
- Ask a question in the slack channel
- Email us at [email protected]
Impact
CVE-2022-21704 has a CVSS score of 5.5 (Medium). The vector is requires local access, low privileges required, and no user interaction. 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 (6.4.0); 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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Frequently Asked Questions
- What is CVE-2022-21704? CVE-2022-21704 is a medium-severity security vulnerability in log4js (npm), affecting versions < 6.4.0. It is fixed in 6.4.0.
- How severe is CVE-2022-21704? CVE-2022-21704 has a CVSS score of 5.5 (Medium). 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 log4js are affected by CVE-2022-21704? log4js (npm) versions < 6.4.0 is affected.
- Is there a fix for CVE-2022-21704? Yes. CVE-2022-21704 is fixed in 6.4.0. Upgrade to this version or later.
- Is CVE-2022-21704 exploitable, and should I be worried? Whether CVE-2022-21704 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-2022-21704 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-2022-21704? Upgrade
log4jsto 6.4.0 or later.