{"id":"CVE-2026-47684","aliases":["EUVD-2026-37123","GHSA-q4x5-8cj6-52wg"],"status":"published","title":"Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP","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.","severity":{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00222,"percentile":0.12829,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-918"],"published":"2026-06-05T16:34:59Z","modified":"2026-10-28T02:31:08Z","fixes":[{"ecosystem":"npm","package":"@sync-in/server","fixed_in":["2.3.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@sync-in/server","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.2.1"},{"fixed":"2.3.0"}]}]},{"source":"osv","ecosystem":"npm","package":"@sync-in/server","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.3.0"}]}]}],"products":[{"vendor":"devolutions","product":"server"},{"vendor":"sync-in","product":"server"}],"references":[{"url":"https://github.com/Sync-in/server/security/advisories/GHSA-q4x5-8cj6-52wg","tags":["x_refsource_CONFIRM","exploit","advisory","web"]},{"url":"https://github.com/Sync-in/server/releases/tag/v2.3.0","tags":["x_refsource_MISC","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-47684","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-q4x5-8cj6-52wg"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/47xxx/CVE-2026-47684.json","tags":["advisory"]},{"url":"https://github.com/Sync-in/server","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-47684","title":"Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP","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.","status":"published","published":"2026-06-16T14:31:30.807Z","modified":"2026-06-16T17:10:12.548Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"high","assessor":"cna"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T13:36:29.327819Z"}],"euvd":[{"id":"EUVD-2026-37123","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.","status":"published","published":"2026-06-16T14:31:30Z","modified":"2026-06-16T17:10:12Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"high"}],"updated_at":"2026-11-02T18:20:40.24472Z"}],"ghsa":[{"id":"GHSA-q4x5-8cj6-52wg","title":"Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP","description":"Summary:\nThe 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.\n\nAffected components\n\nbackend/src/applications/files/services/files-manager.service.ts – downloadFromUrl() checks regExpPrivateIP against request.socket.remoteAddress.\nbackend/src/applications/files/utils/url-file.ts – regExpPrivateIP does not include ::ffff:\u003cipv4\u003e variants.\n\nDetails:\nThe 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.\n\nPoC:\n[poc.pdf](https://github.com/user-attachments/files/26990874/poc.pdf)\n\n\n\n\nProof:\n\u003cimg width=\"1080\" height=\"842\" alt=\"1000226655\" src=\"https://github.com/user-attachments/assets/797cea83-0a08-4a16-a91b-31c51068d473\" /\u003e\n\n\n\n\n\nImpact:\nAn attacker can supply a crafted URL pointing to an internal address that gets reported as ::ffff:127.0.0.1 or ::ffff:10.x.x.x, causing the server to fetch internal resources that should be blocked. Any user with access to the file download feature is a potential attacker.","status":"published","published":"2026-06-05T16:34:59Z","modified":"2026-07-08T17:36:18Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"high"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:40:40.389795Z"}],"nvd":[{"id":"CVE-2026-47684","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.","status":"published","published":"2026-06-16T15:16:41.063Z","modified":"2026-10-25T23:10:00.167Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"high","assessor":"secondary"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:12:24.19758Z"}],"osv":[{"id":"CVE-2026-47684","title":"Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP","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.","status":"published","published":"2026-06-16T14:31:30.807Z","modified":"2026-10-28T02:31:08.207604197Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"high"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:45:06.231145Z"},{"id":"GHSA-q4x5-8cj6-52wg","title":"Sync-in Server: SSRF protection bypass via IPv4-mapped IPv6 addresses in regExpPrivateIP","description":"Summary:\nThe 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.\n\nAffected components\n\nbackend/src/applications/files/services/files-manager.service.ts – downloadFromUrl() checks regExpPrivateIP against request.socket.remoteAddress.\nbackend/src/applications/files/utils/url-file.ts – regExpPrivateIP does not include ::ffff:\u003cipv4\u003e variants.\n\nDetails:\nThe 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.\n\nPoC:\n[poc.pdf](https://github.com/user-attachments/files/26990874/poc.pdf)\n\n\n\n\nProof:\n\u003cimg width=\"1080\" height=\"842\" alt=\"1000226655\" src=\"https://github.com/user-attachments/assets/797cea83-0a08-4a16-a91b-31c51068d473\" /\u003e\n\n\n\n\n\nImpact:\nAn attacker can supply a crafted URL pointing to an internal address that gets reported as ::ffff:127.0.0.1 or ::ffff:10.x.x.x, causing the server to fetch internal resources that should be blocked. Any user with access to the file download feature is a potential attacker.","status":"published","published":"2026-06-05T16:34:59Z","modified":"2026-07-08T17:45:18.193904281Z","cvss":[{"version":"3.1","score":7.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N","level":"high"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:46:54.055966Z"}]}}