DEBIAN-CVE-2021-21290

Advisory lineage Upstream: 1 Downstream: 2
Upstream
CVE-2021-21290
Published: 08 Feb 2021, 20:15
Last modified:28 Apr 2026, 20:22

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
3.1 (osv_debian)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

08 Feb 2021, 20:15
Published
Vulnerability first disclosed
28 Apr 2026, 20:22
Last Modified
Vulnerability information updated

Description

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.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected Systems

  • debian•netty

    < 1:4.1.48-2 | < 1:4.1.48-2 | < 1:4.1.48-2 | < 1:4.1.48-2

References (1)