GHSA-vg6v-j97m-h5xq: @novu/application-generic: `validateUrlSsrf` permits CGNAT (100.64.0.0/10) destinations — affects Workflow HTTP request step + Webhook filter condition
Hi Novu team,
Reporting an SSRF blocklist gap in the shared validateUrlSsrf guard. A complete self-contained reproduction is inlined below — copy the four files into a directory and run docker compose up, plus a single-file probe that runs against Node directly. Locally validated against HEAD 291817c.
Summary
Novu's shared SSRF guard validateUrlSsrf(url) is used before server-side requests to user-configured URLs. The guard resolves hostnames and blocks a regex list of private/reserved IP ranges, but it does not block 100.64.0.0/10 shared address space. As a result, Novu features protected by this guard can still send server-side requests to destinations such as 100.100.100.200 (Alibaba Cloud metadata service) and any other service reachable in 100.64.0.0/10.
Affected code
Guard:
- libs/application-generic/src/utils/ssrf-url-validation.ts
- isPrivateIp(...) regex list at lines 9-28
- DNS resolution and address validation at lines 55-72
Product call-sites:
- Workflow HTTP request step: apps/worker/src/app/workflow/usecases/send-message/execute-http-request-step.usecase.ts — calls validateUrlSsrf(url) at line 149, then uses HttpClientService to send the request.
- Webhook filter condition: libs/application-generic/src/usecases/conditions-filter/conditions-filter.usecase.ts — calls validateUrlSsrf(child.webhookUrl) at line 265, then sends axios.post(child.webhookUrl, ...) at line 277.
HTTP client:
- libs/application-generic/src/services/http-client/http-client.service.ts — uses got(gotOptions) at lines 120 and 142 after the preflight validation.
Root cause
The SSRF guard uses a hand-written regex deny-list:
/^0\.0\.0\.0$/i,
/^127\./,
/^10\./,
/^172\.(1[6-9]|2[0-9]|3[01])\./,
/^192\.168\./,
/^169\.254\./,
/^::ffff:127\./i,
/^::ffff:10\./i,
/^::ffff:172\.(1[6-9]|2[0-9]|3[01])\./i,
/^::ffff:192\.168\./i,
/^::ffff:169\.254\./i,
/^::1$/,
/^fc00:/i,
/^fe80:/i,
This list omits 100.64.0.0/10, also called shared address space or CGNAT. These addresses are not RFC1
Details
Original advisory: https://github.com/advisories/GHSA-vg6v-j97m-h5xq
More from GitHub Security Advisories
- mediumGHSA-jr6p-8pjj-mfx6: Capsule has an incomplete fix of CVE-2026-22872: TenantResource RawItems and Generators s…2026-07-31
- mediumGHSA-68cj-mvg9-rgm2: Capsule: CapsuleConfiguration NodeMetadata regex fields lack webhook validation, allowing…2026-07-31
- mediumGHSA-ff84-5f28-78qj: re2: Out-of-bounds heap read in `exec`/`test`/`match` via attacker-influenced `lastIndex`…2026-07-31
- mediumGHSA-6hxr-mr5r-9836: re2: Global `String.prototype.match` with an empty-matchable pattern never advances → inf…2026-07-31
- mediumGHSA-x83g-979r-f5fh: Sylius Mollie Plugin has unauthenticated IDOR that leaks order token and customer PII2026-07-31