CVE-2021-32842

low-risk
Published 2022-01-26

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.

Do I need to act?

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0.30% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
4
CVSS 4.0/10 Medium
LOCAL / LOW complexity

Affected Products (1)

Sharpziplib

Affected Vendors

20
/ 100
low-risk
Severity 14/34 · Moderate
Exploitability 1/34 · Minimal
Exposure 5/34 · Minimal