ShaneIsrael fireshare up to 1.5.2 Endpoint /api/uploadChunked checkSum path traversal

Summaryinfo

A vulnerability classified as critical has been found in ShaneIsrael fireshare up to 1.5.2. Affected by this vulnerability is an unknown functionality of the file /api/uploadChunked of the component Endpoint. The manipulation of the argument checkSum leads to path traversal. This vulnerability is referenced as CVE-2026-34745. Remote exploitation of the attack is possible. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, has been found in ShaneIsrael fireshare up to 1.5.2. This issue affects some unknown processing of the file /api/uploadChunked of the component Endpoint. The manipulation of the argument checkSum with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to 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. Impacted is integrity, and availability. The summary by CVE is:

Fireshare facilitates self-hosted media and link sharing. Prior to version 1.5.3, the fix for CVE-2026-33645 was applied to the authenticated /api/uploadChunked endpoint but was not applied to the unauthenticated /api/uploadChunked/public endpoint in the same file (app/server/fireshare/api.py). An unauthenticated attacker can exploit the checkSum parameter to write arbitrary files with attacker-controlled content to any writable path on the server filesystem. This issue has been patched in version 1.5.3.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-34745 since 03/30/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1006 for this issue.

Upgrading to version 1.5.3 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying the patch b76915607924756e6fa1a5f6c8823c38d611fb24 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• ShaneIsrael

Name

• fireshare

Version

• 1.5.0
• 1.5.1
• 1.5.2

License

• open-source

Website

• Product: https://github.com/ShaneIsrael/fireshare/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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