CVE-2026-58271

MEDIUMPre-NVD 6.86.8—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 82% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this weekElevated
6.8EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.8Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.8
EG Score
6.8(medium)
EG Risk
47(Track*)
EG Risk 47/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity68% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
18%
KEV
Not listed

Published

September 21, 2026

Last Modified

September 24, 2026

Advisory Details (1)

Auto-updated Sep 21, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

TOTP Brute-Force via `POST /api/app/sync/register` · Advisory · Sync-in/server · GitHub

https://github.com/Sync-in/server/security/advisories/GHSA-274f-6w77-8qm9

Vendor Advisories for CVE-2026-58271(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
@sync-in/server—2.4.0—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 10× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-24 23:38 UTCEG score recompute
  2. 2026-09-24 22:42 UTCEG score recompute
  3. 2026-09-24 21:37 UTCEG score recompute
  4. 2026-09-24 14:04 UTCEPSS rescore
  5. 2026-09-23 23:26 UTCEG score recompute
  6. 2026-09-23 17:54 UTCEPSS rescore
  7. 2026-09-22 21:52 UTCEG score recompute
  8. 2026-09-21 20:18 UTCEG score recompute
  9. 2026-09-21 19:55 UTCEG score recompute
  10. 2026-09-21 19:55 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-58271?
CVE-2026-58271 is a medium vulnerability published on September 21, 2026. 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,…
When was CVE-2026-58271 disclosed?
CVE-2026-58271 was first published in the National Vulnerability Database on September 21, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-58271 actively exploited?
CVE-2026-58271 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 81.9% of all scored CVEs.
What is the CVSS score of CVE-2026-58271?
CVE-2026-58271 has a CVSS v3 base score of 6.8 (NVD).
How do I remediate CVE-2026-58271?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-58271, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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