Upgrade Debian:10 netty to version 1:4.1.33-1+deb10u2 or higher.

Creation of Temporary File With Insecure Permissions in netty | CVE-2021-21290

NVD Description

Note: Versions mentioned in the description apply only to the upstream netty package and not the netty package as distributed by Debian. See How to fix? for Debian:10 relevant fixed versions and status.

Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty before version 4.1.59.Final there is a vulnerability on Unix-like systems involving an insecure temp file. 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. On unix-like systems, the temporary directory is shared between all user. As such, writing to this directory using APIs that do not explicitly set the file/directory permissions can lead to information disclosure. Of note, this does not impact modern MacOS Operating Systems. The method "File.createTempFile" on unix-like systems creates a random file, but, by default will create this file with the permissions "-rw-r--r--". Thus, if sensitive information is written to this file, other local users can read this information. This is the case in netty's "AbstractDiskHttpData" is vulnerable. This has been fixed in version 4.1.59.Final. As a workaround, one may 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.

Creation of Temporary File With Insecure Permissions Affecting netty package, versions <1:4.1.33-1+deb10u2

Severity

Threat Intelligence

Do your applications use this vulnerable package?

Snyk Learn

Introduced: 8 Feb 2021

How to fix?

NVD Description

References

CVSS Scores

NVD

Red Hat