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GHSA-269g-pwp5-87pp

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GHSA-269g-pwp5-87pp

Published: 12 Oct 2020Last Modified: 10 Sept 2026

Aliases:

CVE-2020-15250

Summary: TemporaryFolder on unix-like systems does not limit access to created files

Details: ### Vulnerability The JUnit4 test rule [TemporaryFolder](https://junit.org/junit4/javadoc/4.13/org/junit/rules/TemporaryFolder.html) contains a local information disclosure vulnerability. Example of vulnerable code: ```java public static class HasTempFolder { @Rule public TemporaryFolder folder = new TemporaryFolder(); @Test public void testUsingTempFolder() throws IOException { folder.getRoot(); // Previous file permissions: `drwxr-xr-x`; After fix:`drwx------` File createdFile= folder.newFile("myfile.txt"); // unchanged/irrelevant file permissions File createdFolder= folder.newFolder("subfolder"); // unchanged/irrelevant file permissions // ... } } ``` ### Impact On Unix like systems, the system's temporary directory is shared between all users on that system. Because of this, when files and directories are written into this directory they are, by default, readable by other users on that same system. This vulnerability **does not** allow other users to overwrite the contents of these directories or files. This is purely an information disclosure vulnerability. When analyzing the impact of this vulnerability, here are the important questions to ask: 1. Do the JUnit tests write sensitive information, like API keys or passwords, into the temporary folder? - If yes, this vulnerability impacts you, but only if you also answer 'yes' to question 2. - If no, this vulnerability does not impact you. 2. Do the JUnit tests ever execute in an environment where the OS has other untrusted users. _This may apply in CI/CD environments but normally won't be 'yes' for personal developer machines._ - If yes, and you answered 'yes' to question 1, this vulnerability impacts you. - If no, this vulnerability does not impact you. ### Patches Because certain JDK file system APIs were only added in JDK 1.7, this this fix is dependent upon the version of the JDK you are using. - Java 1.7 and higher users: this vulnerability is fixed in 4.13.1. - Java 1.6 and lower users: **no patch is available, you must use the workaround below.** ### Workarounds If you are unable to patch, or are stuck running on Java 1.6, specifying the `java.io.tmpdir` system environment variable to a directory that is exclusively owned by the executing user will fix this vulnerability. ### References - [CWE-200: Exposure of Sensitive Information to an Unauthorized Actor](https://cwe.mitre.org/data/definitions/200.html) - Fix commit https://github.com/junit-team/junit4/commit/610155b8c22138329f0723eec22521627dbc52ae #### Similar Vulnerabilities - Google Guava - https://github.com/google/guava/issues/4011 - Apache Ant - https://nvd.nist.gov/vuln/detail/CVE-2020-1945 - JetBrains Kotlin Compiler - https://nvd.nist.gov/vuln/detail/CVE-2020-15824 ### For more information If you have any questions or comments about this advisory, please pen an issue in [junit-team/junit4](https://github.com/junit-team/junit4/issues).

Affected packages

Package

Name: junit:junit

Purl: pkg:maven/junit/junit

Affected ranges

Type: ECOSYSTEM

Events:

Introduced- 4.7

Fixed -4.13.1

Affected versions

4.10

Common Vulnerability Scoring System

Attack Vector

Network

Adjacent

Local

Physical

Privileges Required

None

Low

High

User Interaction

None

Required

Scope

Unchanged

Changed

Confidentiality

None

Low

High

Integrity

None

Low

High

Availability

None

Low

High