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

Source: https://junglewise.ai/threats/cve-2026-35036-ech0-has-unauthenticated-server-side-request-forgery-in-website  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-06  
License: CC BY 4.0 with a link back

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)](https://junglewise.ai/threats/technologies/github-com-lin-snow-ech0). Vendors: [Go](https://junglewise.ai/threats/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

  ```sh
  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

## Related threats

- [Ech0 scope bypass in PUT /user endpoint via profile:read token](https://junglewise.ai/threats/cve-2026-79673-ech0-scope-bypass-in-put-user-endpoint-via-profile-read-token)
- [Ech0 authorization bypass in comment panel endpoints](https://junglewise.ai/threats/cve-2026-79672-ech0-authorization-bypass-in-comment-panel-endpoints)
- [Ech0 server-side request forgery in webhook URL validation](https://junglewise.ai/threats/cve-2026-79671-ech0-server-side-request-forgery-in-webhook-url-validation)
- [Ech0 stored cross-site scripting in file upload](https://junglewise.ai/threats/cve-2026-79670-ech0-stored-cross-site-scripting-in-file-upload)
- [Ech0 missing authorization on system log endpoints](https://junglewise.ai/threats/cve-2026-79669-ech0-missing-authorization-on-system-log-endpoints)