CVE-2026-79671 json
Ech0 before 4.4.3 SSRF via DNS Resolution Bypass
published 2026-04-10 6 mo ago modified 2026-08-31 2 mo ago also GHSA-r2x7-427f-rq69 , GO-2026-5603 , EUVD-2026-65443
- cvss
- 5.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 24%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- go github.com/lin-snow/ech0 4.4.3
- lin-snow Ech0 4.4.3
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/lin-snow/Ech0/security/advisories/GHSA-r2x7-427f-rq69 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 5.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N |
| CNA | 3.1 | 5.5 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N |
| CNA | 4.0 | 5.1 | CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| GitHub | 3.1 | 5.5 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/lin-snow/ech0 | <4.4.3 all versions |
4.4.3 |
Affected products
- lin-snow Ech0
Classification
- Weakness
-
- CWE-918 Server-Side Request Forgery
References
-
github.com
/lin-snow/Ech0/security/advisories/GHSA-r2x7-427f-rq69
vendor-advisory, exploit, web, advisory
-
vulncheck.com
/advisories/ech0-before-ssrf-via-dns-resolution-bypass
third-party-advisory
-
github.com
/lin-snow/Ech0
package
-
github.com
/lin-snow/Ech0/releases/tag/v4.4.3
web
Sources
- CVE List CVE-2026-79671
- GitHub Advisory GHSA-r2x7-427f-rq69
- NVD CVE-2026-79671
- OSV GO-2026-5603
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.