CVE-2021-32841

Description

SharpZipLib (or #ziplib) is a Zip, GZip, Tar and BZip2 library. Starting version 1.3.0 and prior to version 1.3.3, a check was added if the destination file is under destination directory. However, it is not enforced that `destDir` ends with slash. If the `destDir` is not slash terminated like `/home/user/dir` it is possible to create a file with a name thats begins with the destination directory, i.e. `/home/user/dir.sh`. Because of the file name and destination directory constraints, the arbitrary file creation impact is limited and depends on the use case. Version 1.3.3 contains a patch for this vulnerability.

How to fix CVE-2021-32841

To remediate CVE-2021-32841, upgrade the affected package to a fixed version below.

• —upgrade to 1.3.3 or later

Is CVE-2021-32841 being exploited?

Low — EPSS is 0.4%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

• >= 1.3.0, < 1.3.3

CVSS scores

References (5)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2021-32841
• ADVISORYsecuritylab.github.com/advisories/GHSL-2021-125-sharpziplib
• PATCHgithub.com/icsharpcode/SharpZipLib
• WEBgithub.com/icsharpcode/SharpZipLib/commit/5c3b293de5d65b108e7f2cd0ea8f81c1b8273f78