CVE-2026-79671 Ech0 before 4.4.3 SSRF via DNS Resolution Bypass
An attacker with admin privileges can bypass webhook URL validation to access internal services and cloud metadata endpoints via SSRF.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-79671?
CVE-2026-79671 is a medium-severity server-side request forgery vulnerability in lin-snow Ech0, published on 25 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
Ech0 before 4.4.3 contains a server-side request forgery vulnerability in the validateWebhookURL function (webhook_setting_service.go), which only validates literal IP addresses via net.ParseIP() and fails to reject hostnames that DNS-resolve to private or internal IPs (e.g., 169.254.169.254.nip.io). An attacker with admin privileges can create a webhook with such a hostname to bypass validation and cause the server to make requests to internal services, cloud metadata endpoints, and private network resources. The issue is fixed in 4.4.3.
Weakness: CWE-918
Which versions are affected by CVE-2026-79671?
3 open source packages ship an affected version, including github.com/lin-snow/ech0.
| Package | Affected | Fixed in |
|---|---|---|
github.com/lin-snow/ech0 Go | All versions | None |
github.com/lin-snow/ech0 Go | All versions | 4.4.3 |
github.com/lin-snow/ech0 Go | All versions | 4.4.3 |
How do I fix CVE-2026-79671?
Upgrade github.com/lin-snow/ech0 to 4.4.3 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-79671 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-79671 exists.
Sources
Also known as GHSA-7rwv-fqq2-88c4, GHSA-r2x7-427f-rq69, GO-2026-5603.