{"answers":{"affected":"2 open source packages ship an affected version, including @sync-in/server.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58271 exists.","fix":"Upgrade @sync-in/server to 2.4.0 or later.","what":"CVE-2026-58271 is a medium-severity authentication bypass vulnerability in Sync-in server, published on 21 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-58271 and fix it if it is affected.\n\nWhat it is: CVE-2026-58271 is a medium-severity authentication bypass vulnerability in Sync-in server, published on 21 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58271 exists.\n\nAffected packages and fixed versions:\n- @sync-in/server (npm): affected all versions; fixed in 2.4.0\n- @sync-in/server (npm): affected all versions; fixed in 2.4.0\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-58271/ (Markdown: https://insights.sbomify.com/CVE-2026-58271/index.md)","id":"CVE-2026-58271","markdown":"https://insights.sbomify.com/CVE-2026-58271/index.md","name":"CVE-2026-58271","record":{"aliases":["GHSA-274f-6w77-8qm9"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["account_takeover","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Sync-in server","requires_auth":"low_privilege","summary":"Attackers can brute-force TOTP codes to register sync clients and disable MFA, leading to account takeover.","user_interaction":"not_required","vuln_class":"auth_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[],"cvss":{"score":6.8,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-307","name":"Improper Restriction of Excessive Authentication Attempts"}],"description":"Sync-in Server is an open-source platform for file storage, sharing, collaboration, and syncing. Prior to version 2.4.0, `POST /api/app/sync/register` accepts credentials and a TOTP code to register a desktop sync client. On a failed TOTP, `SyncClientsManager.register()` calls `updateAccesses(user, ip, false)`, which hits a freeze branch that writes `passwordAttempts` back unchanged. The counter never reaches `USER_MAX_PASSWORD_ATTEMPTS` (10) and the lockout gate never fires. A successful guess returns a `{clientId, clientToken}` pair. The token can be exchanged via `POST /api/app/sync/auth/cookie` for a full JWT. While the code is valid, the attacker can also call `POST /api/auth/2fa/disable` to permanently remove MFA. Version 2.4.0 patches the issue.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"@sync-in/server vulnerable to TOTP Brute-Force via `POST /api/app/sync/register`","id":"CVE-2026-58271","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":2,"n_references":1,"next":{"headline":"Sync-in Server has Username/Login Enumeration via Timing Side-Channel on POST /api/auth/login (incomplete fix of the prior timing-attack advisory)","id":"CVE-2026-58272"},"packages":[{"ecosystem":"npm","fixed":["2.4.0"],"introduced":["0"],"last_affected":[],"package":"@sync-in/server","purl":null,"source":"GHSA-274f-6w77-8qm9"},{"ecosystem":"npm","fixed":["2.4.0"],"introduced":["0"],"last_affected":[],"package":"@sync-in/server","purl":"pkg:npm/%40sync-in/server","source":"GHSA-274f-6w77-8qm9"}],"prev":{"headline":"Sync-in Server has a ReDoS via Unsanitized Regex in Sync Diff `pathFilters`","id":"CVE-2026-58270"},"products":["server"],"published":"2026-09-21","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-09-24","vendors":["Sync-in"]},"summary":"Attackers can brute-force TOTP codes to register sync clients and disable MFA, leading to account takeover.","url":"https://insights.sbomify.com/CVE-2026-58271/"}