CVE-2021-29425

Path Traversal and Improper Input Validation in Apache Commons IO

In Apache Commons IO before 2.7, When invoking the method FileNameUtils.normalize with an improper input string, like "//../foo", or "\..\foo", the result would be the same value, thus possibly providing access to files in the parent directory, but not further above (thus "limited" path traversal), if the calling code would use the result to construct a path value.

The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.

CVE-2021-29425 has a CVSS score of 4.8 (Medium). The vector is network-reachable, no 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 (2.7); upgrading removes the vulnerable code path.

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1. What is CVE-2021-29425? CVE-2021-29425 is a medium-severity improper input validation vulnerability in commons-io:commons-io (maven), affecting versions < 2.7. It is fixed in 2.7. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
2. How severe is CVE-2021-29425? CVE-2021-29425 has a CVSS score of 4.8 (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.
3. Which packages are affected by CVE-2021-29425?
   • commons-io:commons-io (maven) (versions < 2.7)
   • com.cosium.vet:vet (maven) (versions >= 1.0, <= 3.22)
   • com.diamondq.common:common-thirdparty.jcasbin (maven) (versions = 1.4.0)
   • com.liferay:com.liferay.sass.compiler.jsass (maven) (versions = 1.0.1)
   • com.virjar:ratel-api (maven) (versions >= 1.0.0, <= 1.3.6)
   • net.hasor:cobble-lang (maven) (versions >= 4.4.1, <= 4.6.2)
   • org.apache.commons:commons-io (maven) (versions = 1.3.2)
   • org.apache.servicemix.bundles:org.apache.servicemix.bundles.commons-io (maven) (versions >= 1.4, <= 1.5)
   • org.checkerframework.annotatedlib:commons-io (maven) (versions >= 2.6, < 2.7)
   • org.smartboot.servlet:servlet-core (maven) (versions >= 0.1.9, <= 0.6)
4. Is there a fix for CVE-2021-29425? Yes. CVE-2021-29425 is fixed in 2.7. Upgrade to this version or later.
5. Is CVE-2021-29425 exploitable, and should I be worried? Whether CVE-2021-29425 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
6. What actually determines whether CVE-2021-29425 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.
7. How do I fix CVE-2021-29425?
   • Upgrade commons-io:commons-io to 2.7 or later
   • Upgrade org.checkerframework.annotatedlib:commons-io to 2.7 or later

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