CVE-2017-6739 — Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability

Summary

A vulnerability in the SNMP implementation of could allow an authenticated, remote attacker to cause a reload of the affected system or to remotely execute code. An attacker could exploit this vulnerability by sending a crafted SNMP packet to the affected device.  The vulnerability is due to a buffer overflow in the affected code area. The vulnerability affects all versions of SNMP (versions 1, 2c, and 3). The attacker must know the SNMP read only community string (SNMP version 2c or earlier) or the user credentials (SNMPv3). An exploit could allow the attacker to execute arbitrary code and obtain full control of the system or to cause a reload of the affected system. Only traffic directed to the affected system can be used to exploit this vulnerability.

Weakness: CWE-119

Title, description and the vendor's statements are quoted from the CVE record; a vendor's advisory is summarised in Patcharo's words, with a link.

Affected and fixed versions

Per product and release branch, as the vendor's CVE record and official advisory state them. A fixed release is shown only when a document names it: the vendor's, or CERT-FR's for Check Point, with its source.

Remediation

Known exploitation

11% probability of exploitation in the next 30 days (percentile 96%).

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CERT-FR

No CERT-FR advisory or alert of the last two years references this CVE, for the vendors Patcharo covers.

Timeline

1. 17 Jul 2017Published by the source
2. 3 Mar 2022Added to CISA KEV
3. 24 Mar 2022CISA remediation due date
4. 17 Jun 2026Source record last modified
5. 29 Sept 2026EPSS score computed
6. 1 Oct 2026Last verified by Patcharo

Official sources

• Cisco (CVE record)retrieved 1 Oct 2026 at 09:31 UTC
• CISA Known Exploited Vulnerabilitiesretrieved 1 Oct 2026 at 09:28 UTC
• NVDretrieved 27 Sept 2026 at 23:44 UTC
• FIRST EPSSretrieved 30 Sept 2026 at 00:17 UTC
• Cisco Security Advisory cisco-sa-20170629-snmpretrieved 1 Oct 2026 at 09:31 UTC

Cisco · CISA Known Exploited Vulnerabilities · NVD · FIRST EPSS · Cisco Security Advisory cisco-sa-20170629-snmp