Sync-in Server has Username/Login Enumeration via Timing Side-Channel on POST /api/auth/login (incomplete fix of the prior timing-attack advisory)

Exploitation

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

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS

• CVE-2026-58272: 0.39% estimated exploitation activity in the next 30 days; percentile 33.59 (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 validateUser() in backend/src/authentication/providers/mysql/auth-provider-mysql.service.ts returns immediately when the supplied login/email does not match any account, without ever calling comparePassword(): async validateUser(loginOrEmail: string, password: string, ip?: string, scope?: AUTHSCOPE): Promise<UserModel { let user: UserModel try { user = await this.usersManager.findUser(loginOrEmail, false) } catch (e) { ... } if (!user) { this.logger.warn(...) return null // <-- comparePassword() is never reached here } return await this.usersManager.logUser(user, password, ip, scope) } comparePassword() (backend/src/common/functions.ts) already contains a dummy-hash branch that was clearly added to defend against exactly this class of attack: export async function comparePassword(password: string, hash?: string | null): Promise<boolean { if (!hash) { // No hash, waste time for time-based attacks await bcrypt.compare(password, DUMMYPASSWORDHASH) return false } return await…

Published by the source

22 Sep 2026, 14:49 UTC

Last modified by the source

22 Sep 2026, 15:00 UTC

Source last checked

26 Oct 2026, 13:02 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-29hq-23m2-2j47

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-29hq-23m2-2j47

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-29hq-23m2-2j47

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

# Patch Next advisory brief: CVE-2026-58272

Advisory: Sync-in Server has Username/Login Enumeration via Timing Side-Channel on POST /api/auth/login (incomplete fix of the prior timing-attack advisory)
IDs: CVE-2026-58272, GHSA-29hq-23m2-2j47
Record: https://patchnext.com/advisories/cve-2026-58272 (revision 3, source checked 26 Oct 2026, 13:02 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
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 2.4.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @sync-in/server: affected <= 2.4.0; fixed in 2.4.1

## 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://github.com/advisories/GHSA-29hq-23m2-2j47 (GitHub-reviewed advisory GHSA-29hq-23m2-2j47 lists affected ranges: npm @sync-in/server >=0 <=2.4.0)
- Verified: https://osv.dev/vulnerability/GHSA-29hq-23m2-2j47 (OSV record GHSA-29hq-23m2-2j47 lists affected ranges: npm @sync-in/server >=0 <2.4.1 (fixed))

Commands are suggestions: review each one before running it.