CVE-2021-32842

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.

• CWE-22
• CWE-22

• https://github.com/icsharpcode/SharpZipLib/releases/tag/v1.3.3Release Notes, Third Party Advisory
• https://securitylab.github.com/advisories/GHSL-2021-125-sharpziplib/Exploit, Third Party Advisory
• https://github.com/icsharpcode/SharpZipLib/releases/tag/v1.3.3Release Notes, Third Party Advisory
• https://securitylab.github.com/advisories/GHSL-2021-125-sharpziplib/Exploit, Third Party Advisory

Published

Jan 26, 2022

Last Modified

Jun 17, 2026

Status

Modified

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