{"id":"CVE-2026-42091","revision":null,"records":[{"revision":"d45f04a3b7dd4b84b9310c70968b1c5d","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-42091","aliases":[],"title":"goshs has Cross-Origin Arbitrary File Write via Missing CSRF on PUT and Wildcard CORS","description":"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.","state":0,"publishedAt":"2026-05-04T17:24:47.89+00:00","modifiedAt":"2026-05-05T14:14:46.121+00:00","affected":[{"ecosystem":"Vendor product","name":"goshs","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"patrickhener\",\n                    \"product\": \"goshs\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 2.0.2\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N","score":6.5,"severity":"MEDIUM"}],"references":["https://github.com/patrickhener/goshs/security/advisories/GHSA-rhf7-wvw3-vjvm","https://github.com/patrickhener/goshs/commit/0e715b94e10c3d1aa552276000f15f104dee2f32","https://github.com/patrickhener/goshs/releases/tag/v2.0.2"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-42091","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-42091","identifiers":["CVE-2026-42091"]},"retained":false,"historicalAffected":[]},{"revision":"d7c617fb50e5403f9eda03ffe8ca289f","observedAt":"2026-11-07T09:32:09.395+00:00","statement":{"source":"euvd","id":"EUVD-2026-27067","aliases":["CVE-2026-42091"],"title":"goshs is a SimpleHTTPServer written in Go. 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This issue has been patched in version 2.0.2.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N","score":6.5,"severity":null}],"references":["https://github.com/patrickhener/goshs/security/advisories/GHSA-rhf7-wvw3-vjvm","https://github.com/patrickhener/goshs/commit/0e715b94e10c3d1aa552276000f15f104dee2f32","https://github.com/patrickhener/goshs/releases/tag/v2.0.2"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-27067","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"May 4, 2026, 5:24:47 PM","dateUpdated":"May 5, 2026, 2:14:46 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-27067","identifiers":["EUVD-2026-27067","CVE-2026-42091"]},"retained":false,"historicalAffected":[]},{"revision":"8d6c777b9ff74aac80d7b986d1ffa903","observedAt":"2026-10-27T11:12:01.124+00:00","statement":{"source":"nvd","id":"CVE-2026-42091","aliases":[],"title":"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 unco…","description":"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.","state":0,"publishedAt":"2026-05-04T18:16:31.21+00:00","modifiedAt":"2026-10-26T19:10:00.163+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N","score":6.5,"severity":"MEDIUM"}],"references":["https://github.com/patrickhener/goshs/commit/0e715b94e10c3d1aa552276000f15f104dee2f32","https://github.com/patrickhener/goshs/releases/tag/v2.0.2","https://github.com/patrickhener/goshs/security/advisories/GHSA-rhf7-wvw3-vjvm"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-42091","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-352"],"productCriteria":["cpe:2.3:a:goshs:goshs:*:*:*:*:*:go:*:*"],"sourceDates":{"published":"2026-05-04T18:16:31.210","lastModified":"2026-10-26T19:10:00.163"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-42091","identifiers":["CVE-2026-42091"]},"retained":false,"historicalAffected":[]},{"revision":"ba2e2b965996437dbfdc949785641d62","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GHSA-rhf7-wvw3-vjvm","aliases":["CVE-2026-42091","GO-2026-5625"],"title":"goshs has Cross-Origin Arbitrary File Write via Missing CSRF on PUT and Wildcard CORS","description":"### Summary\nThe PUT upload handler (`httpserver/updown.go`) lacks the CSRF token validation that was added to the POST upload handler during the GHSA-jrq5-hg6x-j6g3 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).\n\n### Details\n**Root Cause 1 — Missing CSRF on PUT** (`httpserver/updown.go:19`)\n\nWhen GHSA-jrq5-hg6x-j6g3 was fixed (commit `e3c3d37`), `checkCSRF()` was added to the POST `upload()` function (line 78) but not to the PUT `put()` function directly above it in the same file. This means PUT requests are accepted without any CSRF token.\n\n```go\n// POST — protected \nfunc (fs *FileServer) upload(w http.ResponseWriter, req *http.Request) {\n    if !fs.checkCSRF(w, req) { return }\n    // ...\n}\n\n// PUT — unprotected \nfunc (fs *FileServer) put(w http.ResponseWriter, req *http.Request) {\n    // No checkCSRF call\n    // ...\n}\n```\n\n**Root Cause 2 — Wildcard CORS** (`httpserver/server.go:126`)\n\nThe OPTIONS handler unconditionally returns permissive CORS headers:\n\n```go\nw.Header().Set(\"Access-Control-Allow-Origin\", \"*\")\nw.Header().Set(\"Access-Control-Allow-Methods\", \"POST, PUT, OPTIONS\")\nw.Header().Set(\"Access-Control-Allow-Headers\", \"Content-Type, Authorization\")\n```\n\nThis allows any website's JavaScript to pass the browser's CORS preflight check and send PUT requests to the goshs server.\n\n### PoC\n[poc.zip](https://github.com/user-attachments/files/26828829/poc.zip)\n\nPlease extract the uploaded compressed file before proceeding\n\n1. bash poc.sh\n<img width=\"543\" height=\"376\" alt=\"스크린샷 2026-04-17 오후 11 08 13\" src=\"https://github.com/user-attachments/assets/a695cbc8-133e-4e80-a2f5-9fe9fd36b569\" />\n\n\n\n\n### Impact\n- Arbitrary file write to the goshs webroot from any website the victim visits\n- File overwrite — existing files can be silently replaced","state":0,"publishedAt":"2026-04-23T14:28:14+00:00","modifiedAt":"2026-06-25T23:11:45.11894+00:00","affected":[{"ecosystem":"Go","name":"github.com/patrickhener/goshs/v2","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"2.0.2"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"Go","name":"github.com/patrickhener/goshs","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"last_affected","version":"1.1.4"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/patrickhener/goshs/security/advisories/GHSA-rhf7-wvw3-vjvm","https://nvd.nist.gov/vuln/detail/CVE-2026-42091","https://github.com/patrickhener/goshs/commit/0e715b94e10c3d1aa552276000f15f104dee2f32","https://github.com/patrickhener/goshs","https://github.com/patrickhener/goshs/releases/tag/v2.0.2"],"sourceUrl":"https://github.com/advisories/GHSA-rhf7-wvw3-vjvm","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-rhf7-wvw3-vjvm","identifiers":["GHSA-rhf7-wvw3-vjvm","CVE-2026-42091","GO-2026-5625"]},"retained":false,"historicalAffected":[]},{"revision":"16ccefb9f3cd48949eb4d2d3189c6ebf","observedAt":"2026-10-24T13:19:41.952+00:00","statement":{"source":"osv","id":"GO-2026-5625","aliases":["CVE-2026-42091","GHSA-rhf7-wvw3-vjvm"],"title":"goshs has Cross-Origin Arbitrary File Write via Missing CSRF on PUT and Wildcard CORS in github.com/patrickhener/goshs","description":"goshs has Cross-Origin Arbitrary File Write via Missing CSRF on PUT and Wildcard CORS in github.com/patrickhener/goshs","state":0,"publishedAt":"2026-06-25T22:34:34+00:00","modifiedAt":"2026-06-25T23:01:36.4969697+00:00","affected":[{"ecosystem":"Go","name":"github.com/patrickhener/goshs","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"Go","name":"goshs.de/goshs","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"}]}],"versions":[],"rawVersionEvidence":null},{"ecosystem":"Go","name":"goshs.de/goshs/v2","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"0"},{"kind":"fixed","version":"2.0.2"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[],"references":["https://github.com/patrickhener/goshs/security/advisories/GHSA-rhf7-wvw3-vjvm","https://nvd.nist.gov/vuln/detail/CVE-2026-42091","https://github.com/patrickhener/goshs/commit/0e715b94e10c3d1aa552276000f15f104dee2f32","https://github.com/patrickhener/goshs/releases/tag/v2.0.2"],"sourceUrl":"https://osv.dev/vulnerability/GO-2026-5625","license":"OSV · upstream source license applies","key":"osv:GO-2026-5625","identifiers":["GO-2026-5625","CVE-2026-42091","GHSA-rhf7-wvw3-vjvm"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. 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