CVE-2026-42091 — goshs has Cross-Origin Arbitrary File Write via Missing CSRF on PUT and Wildcard CORS
goshs is a SimpleHTTPServer written in Go. Prior to version 2.0.2, the PUT upload handler (httpserver/updown.go) lacks the CSRF token validation that was added to the POST uploa…
Published: 2026-05-04 · CVSS: 6.5 · CVSS 3.1
goshs is a SimpleHTTPServer written in Go. Prior to version 2.0.2, the PUT upload handler (httpserver/updown.go) lacks the CSRF token validation that was added to the POST upload handler during the CVE-2026-40883 fix. Combined with the unconditional Access-Control-Allow-Origin: * on the OPTIONS preflight handler (httpserver/server.go), any website can write arbitrary files to a goshs instance through the victim's browser — bypassing network isolation (e.g. localhost, internal network). This issue has been patched in version 2.0.2.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7