Information Disclosure Affecting io.netty:netty-handler package, versions [4.0.0.Final, 4.1.59.Final)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-JAVA-IONETTY-1082235
- published9 Feb 2021
- disclosed9 Feb 2021
- creditJonathan Leitschuh
Introduced: 9 Feb 2021
CVE-2021-21290 (opens in a new tab)How to fix?
Upgrade io.netty:netty-handler to version 4.1.59.Final or higher.
Overview
io.netty:netty-handler is a library that provides an asynchronous event-driven network application framework and tools for rapid development of maintainable high performance and high scalability protocol servers and clients. In other words, Netty is a NIO client server framework which enables quick and easy development of network applications such as protocol servers and clients. It greatly simplifies and streamlines network programming such as TCP and UDP socket server.
Affected versions of this package are vulnerable to Information Disclosure via the AbstractDiskHttpData method, and on Unix-like systems.
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 are enabled.
On unix-like systems, the temporary directory is shared between all users. As such, writing to this directory using API's that do not explicitly set the file/directory permissions can lead to information disclosure.
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--. Sensitive information is written to this file in AbstractDiskHttpData, and other local users can read it.