Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.7 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

EPSS

• CVE-2026-47684: 0.22% estimated exploitation activity in the next 30 days; percentile 12.80 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary: The private IP blocklist regex used in the URL download feature does not match IPv4-mapped IPv6 addresses (e.g. ::ffff:127.0.0.1), allowing SSRF protection to be bypassed on dual-stack systems. Affected components backend/src/applications/files/services/files-manager.service.ts – downloadFromUrl() checks regExpPrivateIP against request.socket.remoteAddress. backend/src/applications/files/utils/url-file.ts – regExpPrivateIP does not include ::ffff:<ipv4 variants. Details: The regExpPrivateIP regex in backend/src/applications/files/utils/url-file.ts correctly blocks standard IPv4 private ranges but does not include ::ffff: prefixed variants. On dual-stack systems, Node.js can report a socket's remoteAddress in IPv4-mapped IPv6 form, meaning the check in FilesManager.downloadFromUrl() can be bypassed entirely. PoC: poc.pdf Proof: <img width="1080" height="842" alt="1000226655" src="https://github.com/user-attachments/assets/797cea83-0a08-4a16-a91b-31c51068d473" / Impact: An…

Published by the source

5 Jun 2026, 16:34 UTC

Last modified by the source

8 Jul 2026, 17:45 UTC

Source last checked

26 Oct 2026, 12:56 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-q4x5-8cj6-52wg

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-q4x5-8cj6-52wg

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-47684

Advisory: Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP
IDs: CVE-2026-47684, GHSA-q4x5-8cj6-52wg
Record: https://patchnext.com/advisories/cve-2026-47684 (revision 2, source checked 26 Oct 2026, 12:56 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @sync-in/server 2.3.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @sync-in/server: affected <= 2.2.1; fixed in 2.3.0

## Suggested inspection (read-only)
- `npm ls @sync-in/server --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @sync-in/server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-q4x5-8cj6-52wg (OSV record GHSA-q4x5-8cj6-52wg lists affected ranges: npm @sync-in/server >=0 <2.3.0 (fixed))
- Verified: https://github.com/advisories/GHSA-q4x5-8cj6-52wg (GitHub-reviewed advisory GHSA-q4x5-8cj6-52wg lists affected ranges: npm @sync-in/server >=0 <=2.2.1)

Commands are suggestions: review each one before running it.