CVE-2026-35036 Ech0 Affected by Unauthenticated Server-Side Request Forgery in Website Preview Feature
Unauthenticated attackers can force the Ech0 server to make arbitrary HTTP requests, potentially accessing internal network resources or sensitive data.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-35036?
CVE-2026-35036 is a high-severity server-side request forgery vulnerability in lin-snow Ech0, published on 6 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-918
Which versions are affected by CVE-2026-35036?
3 open source packages ship an affected version, including github.com/lin-snow/ech0. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/lin-snow/ech0 Go | All versions | 1.4.8-0.20260401031029-4ca56fea5ba4 |
github.com/lin-snow/ech0 Go | All versions | 1.4.8-0.20260401031029-4ca56fea5ba4 |
github.com/lin-snow/ech0 Go | All versions | 1.4.8-0.20260401031029-4ca56fea5ba4 |
Products include Ech0 Ech0.
How do I fix CVE-2026-35036?
Upgrade github.com/lin-snow/ech0 to 1.4.8-0.20260401031029-4ca56fea5ba4 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-35036 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-35036 exists.
Other vulnerabilities in lin-snow Ech0
Sources
Also known as GHSA-wc4h-2348-jc3p, GO-2026-5704.