CVE-2022-24823

Description

GHSA-5mcr-gq6c-3hq2 (CVE-2021-21290) contains an insufficient fix for the vulnerability identified.

Impact

When netty's multipart decoders are used local information disclosure can occur via the local system temporary directory if temporary storing uploads on the disk is enabled.

This only impacts applications running on Java version 6 and lower. Additionally, this vulnerability impacts code running on Unix-like systems, and very old versions of Mac OSX and Windows as they all share the system temporary directory between all users.

Vulnerability Details

To fix the vulnerability the code was changed to the following:

    @SuppressJava6Requirement(reason = "Guarded by version check")
    public static File createTempFile(String prefix, String suffix, File directory) throws IOException {
        if (javaVersion() >= 7) {
            if (directory == null) {
                return Files.createTempFile(prefix, suffix).toFile();
            }
            return Files.createTempFile(directory.toPath(), prefix, suffix).toFile();
        }
        if (directory == null) {
            return File.createTempFile(prefix, suffix);
        }
        File file = File.createTempFile(prefix, suffix, directory);
        // Try to adjust the perms, if this fails there is not much else we can do...
        file.setReadable(false, false);
        file.setReadable(true, true);
        return file;
    }

Unfortunately, this logic path was left vulnerable:

        if (directory == null) {
            return File.createTempFile(prefix, suffix);
        }

This file is still readable by all local users.

Patches

Update to 4.1.77.Final

Workarounds

Specify your own java.io.tmpdir when you start the JVM or use DefaultHttpDataFactory.setBaseDir(...) to set the directory to something that is only readable by the current user or update to Java 7 or above.

References

• CWE-378: Creation of Temporary File With Insecure Permissions
• CWE-379: Creation of Temporary File in Directory with Insecure Permissions

For more information

If you have any questions or comments about this advisory:

Open an issue in netty

CVE-2022-24823 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 (4.1.77.Final); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2022-24823? CVE-2022-24823 is a medium-severity security vulnerability in io.netty:netty-codec-http (maven), affecting versions <= 4.1.76.Final. It is fixed in 4.1.77.Final.
2. How severe is CVE-2022-24823? CVE-2022-24823 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.
3. Which versions of io.netty:netty-codec-http are affected by CVE-2022-24823? io.netty:netty-codec-http (maven) versions <= 4.1.76.Final is affected.
4. Is there a fix for CVE-2022-24823? Yes. CVE-2022-24823 is fixed in 4.1.77.Final. Upgrade to this version or later.
5. Is CVE-2022-24823 exploitable, and should I be worried? Whether CVE-2022-24823 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-2022-24823 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-2022-24823? Upgrade io.netty:netty-codec-http to 4.1.77.Final or later.