CVE-2026-42091: goshs is a SimpleHTTPServer written in Go

Q: How do I fix CVE-2026-42091?

goshs: upgrade to 2.0.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-42091 being exploited?

CVE-2026-42091 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-42091 affect?

CVE-2026-42091 affects goshs. Severity is medium (CVSS 6.5). 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

Q: How urgent is CVE-2026-42091?

Priority 29/100. Public exploit reference

Routine

MEDIUM 6.5UPGRADE

CVE-2026-42091 is a medium-severity flaw (CVSS 6.5) affecting goshs. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 isola

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 94%)
CISA exploited list	No
Weakness	CWE-352
Published	2026-05-04
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: goshs

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-04 18:16 UTCPublished CVE record published
2026-10-26 19:10 UTCUpdated Record last modified

goshs goshs UPGRADE

Affected: < 2.0.2

Fixed in: 2.0.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy goshs || rpm -q goshs || goshs --version

2. UPGRADE to 2.0.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade goshs

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade goshs

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-42091?

goshs: upgrade to 2.0.2. Exact commands for each OS are on this page.

Is CVE-2026-42091 being exploited?

CVE-2026-42091 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-42091 affect?

CVE-2026-42091 affects goshs. Severity is medium (CVSS 6.5). 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

How urgent is CVE-2026-42091?

Priority 29/100. Public exploit reference

Related CVEs

CVE-2026-40883 HIGH 8.1 DOWNGRADE goshs is a SimpleHTTPServer written in Go

References

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