Vulnerability · Published Jun 16, 2026 · Assigned by GitHub_M

CVE-2026-47684Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP

High 7.7

In plain English

A high-severity server-side request forgery in server from Sync-in. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.7High

Exploit odds (30 days)0.2%top 87.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Sync-in Server is a secure, open-source platform for file storage, sharing, collaboration, and syncing. Prior to version 2.3.0, 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. Version 2.3.0 fixes the issue.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	@sync-in/server	2.3.0	GHSA-q4x5-8cj6-52wg

Affected products (as reported)

Vendor	Product	Versions
Sync-in	server	< 2.3.0

Weakness: CWE-918 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

References

https://github.com/Sync-in/server/security/advisories/GHSA-q4x5-8cj6-52wg x_refsource_CONFIRM
https://github.com/Sync-in/server/releases/tag/v2.3.0 x_refsource_MISC