CVE-2026-35036: GO-2026-5704 - Ech0 has Unauthenticated Server-Side Request Forgery in Website Preview Feature in github.com/lin-snow/ech0

CVE-2026-35036 · Severity: high · CVSS 7.5 · Published 2026-04-06

Ech0 is an open-source, self-hosted publishing platform for personal idea sharing. Prior to 4.2.8, Ech0 implements link preview (editor fetches a page title) through GET /api/website/title. That is legitimate product behavior, but the implementation is unsafe: the route is unauthenticated, accepts a fully attacker-controlled URL, performs a server-side GET, reads the entire response body into memory (io.ReadAll). There is no host allowlist, no SSRF filter, and InsecureSkipVerify: true on the outbound client. Anyone who can reach the instance can force the Ech0 server to open HTTP/HTTPS URLs of their choice as seen from the server’s network position (Docker bridge, VPC, localhost from the process view). This vulnerability is fixed in 4.2.8.

Technologies: github.com/lin-snow/ech0 (Go). Vendors: Go.

Quick answers

Is CVE-2026-35036 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-35036 being exploited in the wild.
How severe is CVE-2026-35036?
High severity, with a CVSS score of 7.5, published 6 April 2026.
Which products and versions are affected?
github.com/lin-snow/ech0 (Go) SEMVER:introduced=0,fixed=1.4.8-0.20260401031029-4ca56fea5ba4.
Is there a fix for CVE-2026-35036?
Yes. github.com/lin-snow/ech0 (Go): upgrade to 1.4.8-0.20260401031029-4ca56fea5ba4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-35036?
Check whether you run Ech0 or github.com/lin-snow/ech0 (Go) 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 1.4.8-0.20260401031029-4ca56fea5ba4 or later
    go get github.com/lin-snow/ech0@v1.4.8-0.20260401031029-4ca56fea5ba4

Affected products

  • Ech0
  • github.com/lin-snow/ech0 (Go) SEMVER:introduced=0,fixed=1.4.8-0.20260401031029-4ca56fea5ba4

Identifiers

  • CVE-2026-35036
  • GHSA-wc4h-2348-jc3p
  • GO-2026-5704

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