What’s Vulnerable › Vulnerabilities

CVE-2026-42091: goshs has Cross-Origin Arbitrary File Write via Missing CSRF on PUT and Wildcard CORS

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-04 · updated 2026-10-26
• Weakness: CWE-352

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.

Affected products

• patrickhener goshs: before 2.0.2 — fixed in 2.0.2

How to fix

Upgrade to a fixed version: patrickhener goshs 2.0.2. Check the vendor advisory for mitigations.

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
• https://github.com/patrickhener/goshs/security/advisories/GHSA-rhf7-wvw3-vjvm

Get alerted when CVE-2026-42091 or the next vulnerability affects your stack