What is CVE-2015-7256?

CVE-2015-7256 is a medium-severity vulnerability in Zyxel C1000z, classified under Cryptographic Issues. CVSS score: 5.9/10. Published 2017-09-28.

How severe is CVE-2015-7256?

Medium severity. CVSS v3 base score is 5.9 out of 10.

Vulnerability in Zyxel C1000z

CVE-2015-7256

ZyXEL NWA1100-N, NWA1100-NH, NWA1121-NI, NWA1123-AC, and NWA1123-NI access points; P-660HN-51, P-663HN-51, VMG1312-B10A, VMG1312-B30A, VMG1312-B30B, VMG4380-B10A, VMG8324-B10A, VMG8924-B10A, VMG8924-B30A, and VSG1435-B101 DSL CPEs; PMG5318-B20A GPONs; SBG3300-N000, SBG3300-NB00, and SBG3500-N000 small business gateways; GS1900-8 and GS1900-24 switches; and C1000Z, Q1000, FR1000Z, and P8702N project models use non-unique X.509 certificates and SSH host keys.

Vulnerability class: POODLE (CVE-2014-3566)

Published 2017-09-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.008 (55.9th percentile), scored 2026-10-23.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 55.9% 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

Weakness classification (CWE)

CWE-310 — Cryptographic Issues

References

www.kb.cert.org/vuls/id/566724 (US Government Resource, Third Party Advisory, third-party-advisory)
www.zyxel.com/support/announcement_SSH_private_key_and_certificate_vulnerabilit… (Vendor Advisory)

Frequently asked questions

What is CVE-2015-7256?: CVE-2015-7256 is a medium-severity vulnerability in Zyxel C1000z, classified under Cryptographic Issues. CVSS score: 5.9/10. Published 2017-09-28.
How severe is CVE-2015-7256?: Medium severity. CVSS v3 base score is 5.9 out of 10.