CVE-2026-43888
Zip Slip Vulnerability in Outline Document Collaboration Service
Publication date: 2026-05-11
Last updated on: 2026-05-11
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
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Meta Information
Affected Vendors & Products
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-22 | The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in the Outline service prior to version 1.7.0, specifically in the ZipHelper.extract function. When extracting files from a zip archive, if a nested path inside the zip is long enough to exceed the maximum allowed path length (4096 bytes), the filename helper trimFileAndExt drops all directory components and returns only a bare filename. As a result, the file is extracted outside the intended extraction sandbox, into the process's working directory. This escaped file remains after the import cleanup because the cleanup process only removes the temporary extraction directory.
How can this vulnerability impact me? :
This vulnerability can lead to files being extracted outside the intended safe directory, potentially overwriting or creating files in arbitrary locations on the filesystem. Because the escaped files persist after cleanup, this can be exploited to place malicious files or manipulate existing files, leading to high impact on integrity and availability of the system.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, upgrade the Outline service to version 1.7.0 or later, where the issue has been fixed.