What is CVE-2017-12259?

CVE-2017-12259 is a high-severity vulnerability in Cisco Small Business Ip Phone, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.5/10. Published 2017-10-19.

How severe is CVE-2017-12259?

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

Buffer overflow in Cisco Small Business Ip Phone

CVE-2017-12259

A vulnerability in the implementation of Session Initiation Protocol (SIP) functionality in Cisco Small Business SPA51x Series IP Phones could allow an unauthenticated, remote attacker to cause an affected device to become unresponsive, resulting in a denial of service (DoS) condition. The vulnerability is due to the improper handling of SIP request messages by an affected device. An attacker could exploit this vulnerability by sending malformed SIP messages to an affected device. A successful exploit could allow the attacker to cause the affected device to become unresponsive, resulting in a DoS condition that persists until the device is restarted manually. This vulnerability affects Cisco Small Business SPA51x Series IP Phones that are running Cisco SPA51x Firmware Release 7.6.2SR1 or earlier. Cisco Bug IDs: CSCvc63982.

Vulnerability class: Buffer Overflow

Published 2017-10-19 · 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:N/A:H.

EPSS exploit prediction

EPSS: 0.023 (82.7th percentile), scored 2026-10-06.

Low probability of exploitation in the next 30 days, but still tracked. 83rd percentile — 82.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.023 · newest: 0.023 · change: 0.000

Affected products

Cisco Small Business Ip Phone — versions spa510
Cisco Small Business Ip Phone Firmware
Cisco Small Business Spa51x Series Ip Phones — versions Cisco Small Business SPA51x Series IP Phones

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

References

tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171018… (Vendor Advisory)
www.securitytracker.com/id/1039615 (VDB Entry, Third Party Advisory, vdb-entry)
www.securityfocus.com/bid/101488 (VDB Entry, Third Party Advisory, vdb-entry)

Frequently asked questions

What is CVE-2017-12259?: CVE-2017-12259 is a high-severity vulnerability in Cisco Small Business Ip Phone, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.5/10. Published 2017-10-19.
How severe is CVE-2017-12259?: High severity. CVSS v3 base score is 7.5 out of 10.