What is CVE-2017-1000420?

CVE-2017-1000420 is a high-severity vulnerability in Syncthing, classified under Improper Link Resolution Before File Access. CVSS score: 7.5/10. Published 2018-01-02.

How severe is CVE-2017-1000420?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2017-1000420 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Syncthing

CVE-2017-1000420

Syncthing version 0.14.33 and older is vulnerable to symlink traversal resulting in arbitrary file overwrite

Published 2018-01-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.015 (73.5th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 73rd percentile — 73.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.015 · newest: 0.015 · change: 0.000

Affected products

Syncthing

Weakness classification (CWE)

CWE-59 — Improper Link Resolution Before File Access

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

github.com/syncthing/syncthing/issues/4286 (Patch, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2017-1000420?: CVE-2017-1000420 is a high-severity vulnerability in Syncthing, classified under Improper Link Resolution Before File Access. CVSS score: 7.5/10. Published 2018-01-02.
How severe is CVE-2017-1000420?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2017-1000420 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.