Posit Shiny up to 1.6.3 Bookmark Restore restore handler state_id path traversal

Summaryinfo

A vulnerability marked as problematic has been reported in Posit Shiny up to 1.6.3. This impacts the function restore handler of the component Bookmark Restore. Performing a manipulation of the argument state_id results in path traversal. This vulnerability is reported as CVE-2026-108258. The attack is possible to be carried out remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in Posit Shiny up to 1.6.3. This affects the function restore handler of the component Bookmark Restore. The manipulation of the argument state_id with an unknown input leads to a path traversal vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality. The summary by CVE is:

Shiny for Python is a framework for building interactive web applications in Python. From 1.4.0 until 1.6.4, bookmark restore accepts a client-supplied state_id and joins it into the server-side shiny_bookmarks directory without validating that it is a single safe path segment. An unauthenticated request can use parent-directory segments or an absolute path to make the server open input.json and values.json outside the bookmark store, even when bookmark_store is set to disable. In applications configured with bookmark_store set to server and using ui.input_file(), the restore handler can additionally copy and expose an attacker-selected file from an attacker-selected directory. This issue is fixed in version 1.6.4.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-108258 since 10/09/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

Upgrading to version 1.6.4 eliminates this vulnerability.

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Vendor

• Posit

Name

• Shiny

Version

• 1.6.0
• 1.6.1
• 1.6.2
• 1.6.3

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