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fix: block full 172 private host range #1442

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fix: block full 172 private host range #1442

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9009079
fix: cover full 172 private host range
silentgeckoaudit3801 Jul 23, 2026
f006e5b
test: cover private 172 host detection
silentgeckoaudit3801 Jul 23, 2026
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15 changes: 15 additions & 0 deletions backend/src/__tests__/indexerPrivateHost.test.ts
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Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
import { describe, expect, it } from '@jest/globals';
import { isPrivateHost } from '../controllers/indexerController.js';

describe('isPrivateHost', () => {
it('blocks the full 172.16.0.0/12 private range', () => {
expect(isPrivateHost('172.16.0.1')).toBe(true);
expect(isPrivateHost('172.16.255.254')).toBe(true);
expect(isPrivateHost('172.31.255.254')).toBe(true);
});

it('does not classify neighboring public 172 ranges as private', () => {
expect(isPrivateHost('172.15.255.254')).toBe(false);
expect(isPrivateHost('172.32.0.1')).toBe(false);
});
});

Check failure on line 15 in backend/src/__tests__/indexerPrivateHost.test.ts

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4 changes: 2 additions & 2 deletions backend/src/controllers/indexerController.ts
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Expand Up @@ -20,7 +20,7 @@ import logger from '../utils/logger.js';
* Returns true if the hostname resolves to a private, loopback, or link-local
* address that should never receive outbound webhook deliveries (SSRF guard).
*/
function isPrivateHost(hostname: string): boolean {
export function isPrivateHost(hostname: string): boolean {
// Strip IPv6 brackets
const host = hostname.replace(/^\[|\]$/g, '');

Expand All @@ -34,7 +34,7 @@ function isPrivateHost(hostname: string): boolean {

// Private IPv4 ranges (RFC 1918)
if (/^10\./.test(host)) return true;
if (/^172\.(1[7-9]|2\d|3[01])\./.test(host)) return true;
if (/^172\.(1[6-9]|2\d|3[01])\./.test(host)) return true;
if (/^192\.168\./.test(host)) return true;

// AWS / GCP metadata endpoints
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