CVE-2026-42091

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

MEDIUM
6.5
CVSS Score
Published: May 4, 2026 at 05:24 PM UTC
Updated: October 26, 2026 at 07:10 PM UTC
2 products affected across 2 vendorsGoshsGoshs

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.2%
SSVC
PoC

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.0.2
v < 2.0.2
Affected range stops below 2.0.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/patrickhener/goshs/security/advisories/GHSA-rhf7-wvw3-vjvm
x_refsource_MISCProductRelease Notes
Source: cverecord
https://github.com/patrickhener/goshs/releases/tag/v2.0.2

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-352

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