Security Digest · Vulnerability record
CVE-2026-35393: goshs: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in goshs POST multipart upload
goshs is a SimpleHTTPServer written in Go.
CVSS 9.8 Critical EPSS 0.7% · p52
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.7%, percentile 52: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 52% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
github.com/patrickhener/goshs(Go) < 1.1.5-0.20260401172448-237f3af891a9, fixed in 1.1.5-0.20260401172448-237f3af891a9. Check your lockfile, including transitive dependencies.
What it is
goshs is a SimpleHTTPServer written in Go. Prior to 2.0.0-beta.3, the POST multipart upload directory not sanitized. This vulnerability is fixed in 2.0.0-beta.3.
From the GitHub advisory
Summary POST multipart upload directory not sanitized | httpserver/updown.go:71-174
This finding affect the default configuration, no flags or authentication required.
Details
File: httpserver/updown.go:71-174 Trigger: POST / /upload (server.go:49-51 checks HasSuffix(r.URL.Path, "/upload"))
The filename is sanitized (slashes stripped, line 105-106), but the target directory comes from req.URL.Path unsanitized:
Weakness type: CWE-22.
Product: github.com/patrickhener/goshs (Go) · Assigned by: GitHub_M · Published: 2026-04-06
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Go | github.com/patrickhener/goshs | < 1.1.5-0.20260401172448-237f3af891a9 | 1.1.5-0.20260401172448-237f3af891a9 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| patrickhener | goshs | < 2.0.0-beta.3 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.0 | 9.8 Critical | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.69% probability of exploitation activity in the next 30 days; percentile 52.
Timeline
- — GitHub-reviewed advisory GHSA-jg56-wf8x-qrv5 published (critical)
- — CVE record published by GitHub_M
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-jg56-wf8x-qrv5 github.com
- CVE.org record CVE-2026-35393 cve.org
- NVD entry CVE-2026-35393 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com