What’s Vulnerable › Vulnerabilities

CVE-2021-32841: Path Traversal in SharpZipLib

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-01-26 · updated 2026-06-17
• Weakness: CWE-22

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.

Affected products

• icsharpcode sharpziplib: from 1.3.0 before 1.3.3 — fixed in 1.3.3

How to fix

Upgrade to a fixed version: icsharpcode sharpziplib 1.3.3. Check the vendor advisory for mitigations.

References

• https://github.com/icsharpcode/SharpZipLib/commit/5c3b293de5d65b108e7f2cd0ea8f81c1b8273f78
• https://github.com/icsharpcode/SharpZipLib/releases/tag/v1.3.3
• https://securitylab.github.com/advisories/GHSL-2021-125-sharpziplib/
• https://github.com/icsharpcode/SharpZipLib/commit/5c3b293de5d65b108e7f2cd0ea8f81c1b8273f78
• https://github.com/icsharpcode/SharpZipLib/releases/tag/v1.3.3
• https://securitylab.github.com/advisories/GHSL-2021-125-sharpziplib/

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