Sync-in Server is an open-source platform for file storage, sharing, collaboration, and syncing. Prior to version 2.4.0, the sync diff endpoint compiles a user-supplied string into a RegExp with no complexity validation. A catastrophic-backtracking pattern (e.g. ^(a+)+b) blocks the Node.js event loop, making the entire server unresponsive to all users until the container is restarted. Version 2.4.0 patches the issue.
CVE-2026-58270
MEDIUMPre-NVD 6.56.5—Trending — 3 sources updated this weekElevated
EchelonGraph scoreMEDIUM confidence
This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 74% 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
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: Elevated riskExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.5
- EG Score
- 6.5(medium)
- EG Risk
- 45(Track)EG Risk 45/100SSVC: 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 computedSeverity65% × 45%Exploitation40% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 26%
- 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
ReDoS via Unsanitized Regex in Sync Diff `pathFilters` · Advisory · Sync-in/server · GitHub
https://github.com/Sync-in/server/security/advisories/GHSA-jx63-h26r-8cphVendor Advisories for CVE-2026-58270(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)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| @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 9× in last 7d / 9× 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.
- 2026-09-24 19:38 UTCEG score recompute
- 2026-09-24 14:04 UTCEPSS rescore
- 2026-09-23 17:54 UTCEPSS rescore
- 2026-09-23 17:29 UTCEG score recompute
- 2026-09-22 15:20 UTCEG score recompute
- 2026-09-22 14:31 UTCEG score recompute
- 2026-09-21 21:22 UTCEG score recompute
- 2026-09-21 20:33 UTCEG score recompute
- 2026-09-21 20:32 UTCMITRE cvelistV5first tracked
Related CVEs(same product + same CWE)
Same product
6 shownnpm:@sync-in/server
Frequently asked(5)
What is CVE-2026-58270?
CVE-2026-58270 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, the sync diff endpoint compiles a user-supplied string into a RegExp with no complexity validation. A catastrophic-backtracking pattern (e.g. ^(a+)+b) blocks the Node.js event…
When was CVE-2026-58270 disclosed?
CVE-2026-58270 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-2026-58270 actively exploited?
CVE-2026-58270 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 74.4% of all scored CVEs.
What is the CVSS score of CVE-2026-58270?
CVE-2026-58270 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-58270?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-58270, 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
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-58270
Is Your Infrastructure Affected by CVE-2026-58270?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.