CVE-2026-79659: Ech0 server-side request forgery in fetchPeerConnectInfo

CVE-2026-79659 · Severity: high · CVSS 7.7 · Published 2026-08-25

Ech0 is a peer connection management tool used to establish secure connections between services. A server-side request forgery vulnerability in the fetchPeerConnectInfo function allows authenticated attackers to force the server to make HTTP requests to arbitrary URLs, including internal services and cloud metadata endpoints. An attacker can exploit this to extract sensitive credentials and metadata, potentially leading to lateral movement within cloud environments or internal networks.

Technologies: github.com/lin-snow/ech0 (Go), Lin-Snow Ech0. Vendors: Go, Lin-Snow.

Quick answers

Is CVE-2026-79659 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-79659 being exploited in the wild.
How severe is CVE-2026-79659?
High severity, with a CVSS score of 7.7, published 25 August 2026.
Which products and versions are affected?
github.com/lin-snow/ech0 (Go) SEMVER:introduced=0,fixed=1.4.8-0.20260503040602-091d26d2d942; Lin-Snow Ech0 before 4.7.3.
Is there a fix for CVE-2026-79659?
Yes. github.com/lin-snow/ech0 (Go): upgrade to 1.4.8-0.20260503040602-091d26d2d942 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-79659 attacked?
It is attacked over the network.
Am I affected by CVE-2026-79659?
Check whether you run github.com/lin-snow/ech0 (Go) or Lin-Snow Ech0 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/lin-snow/ech0 (Go): upgrade to 1.4.8-0.20260503040602-091d26d2d942 or later
    go get github.com/lin-snow/ech0@v1.4.8-0.20260503040602-091d26d2d942

Technical details

The vulnerability exists in the fetchPeerConnectInfo function (internal/service/connect/connect.go, lines 214-239) which uses httpUtil.SendRequest to fetch peer connection data without URL validation. The codebase contains a secure alternative, httpUtil.SendSafeRequest, which implements ValidatePublicHTTPURL and blocks private IP ranges, but fetchPeerConnectInfo fails to use it. Authenticated users can supply malicious connect_url parameters pointing to internal services (e.g., 169.254.169.254 for AWS metadata, kubernetes.default.svc.cluster.local for Kubernetes API) and trigger SSRF via health check endpoints or peer connection operations. The vulnerability requires authentication but has no user interaction requirement and can access highly sensitive infrastructure metadata. The fix is available in version 4.7.3.

Affected products

  • lin-snow Ech0 before 4.7.3

Identifiers

  • CVE-2026-79659
  • GHSA-8mc6-xjpr-h98x
  • GO-2026-5259

Timeline

  • 2026-05-03: disclosed: GitHub security advisory published
  • 2026: patched: Patched in version 4.7.3
  • 2026-08-25: advisory: CVE-2026-79659 published

References

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