dssrf: any users using 1.1.1.1 DNS is impacted by SSRF

## Summary is_url_safe can treat localhost as safe when DNS resolver 1.1.1.1 returns NXDOMAIN because dns.resolve4 yields no address and no dns.lookup fallback occurs, allowing server-side request forgery. ## POC Example to simulate 1.1.1.1 in version before 1.5.0 of dssrf: ```js import { is_url_safe } from '../dist/helpers.js'; import dns from 'dns'; dns.setServers(['1.1.1.1']); const TARGET = 'http://localhost/admin'; console.log(`Testing: ${TARGET}`); console.log(`Current DNS Servers: ${dns.getServers()}`); const result = await is_url_safe(TARGET); if (result === true) { console.log('dssrf treated localhost as SAFE because 1.1.1.1 returned NXDOMAIN.'); } else { console.log('dssrf blocked localhost.'); } ```

Source published

31 Jul 2026 16:58:42 UTC

Source modified

31 Jul 2026 17:26:45 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Publisher rating · HIGH