CVE-2021-32842

Summary

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.

Affected Software

VendorProductVersion RangeStatus
icsharpcodesharpziplib1.3.3 < 1.3.3affected
icsharpcodesharpziplib1.0.0 < 1.0.0*affected

Weaknesses

  • CWE-22: CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

ADP Enrichment

CVE Program Container

Additional References

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: no
    • Technical Impact: partial

References