CVE-2021-21290

Publication date 8 February 2021

Last updated 24 July 2024


Ubuntu priority

Cvss 3 Severity Score

5.5 · Medium

Score breakdown

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.

Status

Package Ubuntu Release Status
netty 24.10 oracular
Needs evaluation
24.04 LTS noble
Needs evaluation
23.10 mantic
Fixed 1:4.1.48-2
23.04 lunar Ignored end of life, was needs-triage
22.10 kinetic
Fixed 1:4.1.48-5ubuntu0.1
22.04 LTS jammy
Fixed 1:4.1.48-4+deb11u1build0.22.04.1
21.10 impish Ignored end of life
21.04 hirsute Ignored end of life
20.10 groovy Ignored end of life
20.04 LTS focal
18.04 LTS bionic
16.04 LTS xenial
14.04 LTS trusty
Needs evaluation

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Severity score breakdown

Parameter Value
Base score 5.5 · Medium
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact None
Availability impact None
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N