{"id":"GHSA-43fj-qp3h-hrh5","summary":"Sync-in Server has Username Enumeration via Timing Attack","details":"### Summary\nThe `/api/auth/login` endpoint contains a logic flaw that allows unauthenticated remote attackers to enumerate valid usernames by measuring the application's response time.\n\n### Details\nThe logic flaw can be located at the below point in source:\nhttps://github.com/Sync-in/server/blob/7868bb2b3025f92e6c38087456304758713971b2/backend/src/applications/users/services/users-queries.service.ts#L91-L95\n\nEndpoints used for authentication should respond to the user with a consistent cadence, preventing remote actors from deriving sensitive information about an application based on backend behavior. In the case of authentication endpoints, this timing discrepancy is often caused by short-circuiting due to the lack of a matched user to compare against - as is the case with Sync-in.\n\n### Validation\nTickTock Enum (Burp Suite Extension) was utilized to validate this finding. Authentication attempts with a valid username see a response from the application at around 350-400ms on average, while invalid usernames are returned at only 95-100ms on average.\n\u003cimg width=\"1302\" height=\"284\" alt=\"image\" src=\"https://github.com/user-attachments/assets/31eeb72a-c3c2-4057-ac69-c0c92f0bbd4e\" /\u003e\n\n### Impact\nAn unauthenticated remote attacker can enumerate valid usernames. This significantly weakens the application's security posture by facilitating targeted brute-force attacks, stuffing, social engineering, and a suite of other more targeted attacks.","aliases":["CVE-2026-41161"],"modified":"2026-05-12T17:16:56.945500Z","published":"2026-04-15T18:57:50Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-04-15T18:57:50Z","nvd_published_at":"2026-05-08T14:16:33Z","cwe_ids":["CWE-208"],"severity":"MODERATE"},"references":[{"type":"WEB","url":"https://github.com/Sync-in/server/security/advisories/GHSA-43fj-qp3h-hrh5"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-41161"},{"type":"PACKAGE","url":"https://github.com/Sync-in/server"},{"type":"WEB","url":"https://github.com/Sync-in/server/releases/tag/v2.2.0"}],"affected":[{"package":{"name":"@sync-in/server","ecosystem":"npm","purl":"pkg:npm/%40sync-in/server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"2.2.0"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 2.1.0","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-43fj-qp3h-hrh5/GHSA-43fj-qp3h-hrh5.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"}]}