Vulnerability in Apple Mac OS X

CVE-2015-2851

client_chown in the sync client in Synology Cloud Station 1.1-2291 through 3.1-3320 on OS X allows local users to change the ownership of arbitrary files, and consequently obtain root access, by specifying a filename.

Published 2015-05-30 · last modified 2026-06-17.

CVSS v2 metric

CVSS v2 base score 6.8 (Medium). Vector: AV:L/AC:L/Au:S/C:C/I:C/A:C. This CVE predates CVSS v3 and has no v3 score from NVD.

EPSS exploit prediction

EPSS: 0.008 (53.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 53.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Apple Mac OS X
Synology Cloud Station — versions 1.1-2291, 2.0-2291, 2.0-2402

Weakness classification (CWE)

CWE-264

References

www.securityfocus.com/bid/74826 (vdb-entry)
www.kb.cert.org/vuls/id/BLUU-9VBU45 (US Government Resource, Third Party Advisory)
www.kb.cert.org/vuls/id/551972 (US Government Resource, Third Party Advisory, third-party-advisory)