CVE-2021-39208

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

Published Sep 16, 2021 CVSS 3.1 · 4.3 Medium EPSS 1.2% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2021-2087 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.
Github GHSA Github GHSA GHSA-jp7f-grcv-6mjf Partial path traversal in sharpcompress
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 4, 2024, 1:58 AM
Reserved
Aug 16, 2021, 12:00 AM
Status
Modified
Published
Sep 16, 2021, 3:15 PM
Modified
Jun 17, 2026, 4:03 AM