CVE-2021-32842 MEDIUM

CVE-2021-32842: Path Traversal in SharpZipLib

Vendor Icsharpcode
Product sharpziplib
Weakness CWE-22 · Path traversal
Published January 26, 2022
Last update April 22, 2025

CVSS base score

4.0/10
Attack vector Local
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity Low

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

What the vulnerability does

01Description

SharpZipLib (or #ziplib) is a Zip, GZip, Tar and BZip2 library. Starting version 1.0.0 and prior to version 1.3.3, a check was added if the destination file is under a destination directory. However, it is not enforced that `_baseDirectory` ends with slash. If the _baseDirectory is not slash terminated like `/home/user/dir` it is possible to create a file with a name thats begins as the destination directory one level up from the 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 fixed this vulnerability.

Key dates

02Disclosure timeline

January 26, 2022 CVE published
April 22, 2025 Record updated