Description
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.
Affected products
shaneisrael: fireshare
References4
- github.com/ShaneIsrael/fireshare/security/advisories/GHSA-fvvp-… ExploitMitigationVendor Advisory
- github.com/ShaneIsrael/fireshare/commit/b76915607924756e6fa1a5f… Patch
- github.com/ShaneIsrael/fireshare/pull/520 Issue TrackingPatch
- github.com/ShaneIsrael/fireshare/releases/tag/v1.5.3 Release Notes
Metrics
- CVSS 3.1
-
9.1
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H - EPSS — exploit probability
- 1% percentile: 51 · as of 12 November 2026
- CWE
- CWE-22
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.