CVE-2021-39208

Public Exploit
WriteEntryToDirectory used for an archive extraction is vulnerable to partial path traversal.

Description

SharpCompress is a fully managed C# library to deal with many compression types and formats. Versions prior to 0.29.0 are vulnerable to partial path traversal. SharpCompress recreates a hierarchy of directories under destinationDirectory if ExtractFullPath is set to true in options. In order to prevent extraction outside the destination directory the destinationFileName path is verified to begin with fullDestinationDirectoryPath. However, prior to version 0.29.0, it is not enforced that fullDestinationDirectoryPath ends with slash. If the destinationDirectory 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. This issue is fixed in SharpCompress version 0.29.0.

Category

4.3
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.36%
Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com
Affected: adamhathcock sharpcompress
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-39208?
CVE-2021-39208 has been scored as a medium severity vulnerability.
How to fix CVE-2021-39208?
To fix CVE-2021-39208, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-39208 being actively exploited in the wild?
It is possible that CVE-2021-39208 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-39208?
CVE-2021-39208 affects adamhathcock sharpcompress.
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