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TI-2026-30459 Aliases CVE-2026-42091GHSA-rhf7-wvw3-vjvm

goshs has Cross-Origin Arbitrary File Write via Missing CSRF on PUT and Wildcard CORS

Priority MEDIUM 62CWE-352Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Tampering
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-352.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00165 5th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed goshs (patrickhener): 2.0.2github.com/patrickhener/goshs/v2 (Go): 2.0.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
patrickhenergoshsbefore 2.0.22.0.2Patch availableCNA
—github.com/patrickhener/goshs/v2 (Go)before 2.0.22.0.2Patch availableGHSA-rhf7-wvw3-vjvm
—github.com/patrickhener/goshs (Go)up to 1.1.4—No fix listedGHSA-rhf7-wvw3-vjvm
  • goshs Vendorpatrickhener Affected before 2.0.2 Fixed in 2.0.2 Patch available CNA
  • github.com/patrickhener/goshs/v2 (Go) Vendor— Affected before 2.0.2 Fixed in 2.0.2 Patch available GHSA-rhf7-wvw3-vjvm
  • github.com/patrickhener/goshs (Go) Vendor— Affected up to 1.1.4 Fixed in — No fix listed GHSA-rhf7-wvw3-vjvm

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:goshs:goshs:*:*:*:*:*:go:*:*before 2.0.2Vulnerablepatrickhener
  • cpe:2.3:a:goshs:goshs:*:*:*:*:*:go:*:* Versions before 2.0.2 Vulnerable ·patrickhener

Remediation

  • Fix · CNA goshs (patrickhener) Fixed in 2.0.2
  • Fix · GHSA-rhf7-wvw3-vjvm github.com/patrickhener/goshs/v2 (Go) Fixed in 2.0.2 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-42091
  2. 2026-10-03 Alias added: GHSA-rhf7-wvw3-vjvm

References

Exploit 1

Patch 1

Advisory 1

Other 2

  • TI-2026-29540 goshs: Empty-username SFTP password authentication bypass in goshs CVSS 3.1CRITICAL 9.8
  • TI-2026-27601 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in goshs CVSS 3.0CRITICAL 9.8
  • TI-2026-27529 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in goshs POST multipart upload CVSS 3.0CRITICAL 9.8
  • TI-2026-27528 goshs has an Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in goshs PUT Upload CVSS 3.0CRITICAL 9.8
  • TI-2026-29003 goshs has a file-based ACL authorization bypass in goshs state-changing routes CVSS 4.0CRITICAL 9.3
  • TI-2026-29532 SFTP root escape via prefix-based path validation in goshs CVSS 4.0HIGH 8.7
See all 11 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences