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Vulnerability Intelligence

CVE-2017-6740

HighExploitedPublic exploit

The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple vulnerabilities that could allow an authenticated, remote attacker to remotely execute code on an affected system or cause an affected system to reload.

Published Jul 17, 2017 · Updated Apr 21, 2026

Key Facts

Patch immediately
  • CVE-2017-6740 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting IOS (Cisco), IOS Xe (Cisco), Universal Product.
  • It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 3, 2022. Public exploit code is available.
  • EPSS estimates a 11% probability of exploitation in the next 30 days.
  • Fixed versions are available, including IOS 12.4, IOS Xe 3.17.
  • Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

8.8

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

EPSS (30-day exploit likelihood)

11%

Higher than 95.8% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2017-6740 brief as a PDF

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Description

The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple vulnerabilities that could allow an authenticated, remote attacker to remotely execute code on an affected system or cause an affected system to reload. An attacker could exploit these vulnerabilities by sending a crafted SNMP packet to an affected system via IPv4 or IPv6. Only traffic directed to an affected system can be used to exploit these vulnerabilities. The vulnerabilities are due to a buffer overflow condition in the SNMP subsystem of the affected software. The vulnerabilities affect all versions of SNMP - Versions 1, 2c, and 3. To exploit these vulnerabilities via SNMP Version 2c or earlier, the attacker must know the SNMP read-only community string for the affected system. To exploit these vulnerabilities via SNMP Version 3, the attacker must have user credentials for the affected system. A successful exploit could allow the attacker to execute arbitrary code and obtain full control of the affected system or cause the affected system to reload. Customers are advised to apply the workaround as contained in the Workarounds section below. Fixed software information is available via the Cisco IOS Software Checker. All devices that have enabled SNMP and have not explicitly excluded the affected MIBs or OIDs should be considered vulnerable. There are workarounds that address these vulnerabilities.

Known-Exploited Catalog Listings

CatalogAddedRemediation dueRansomware use
CISA KEVMar 3, 2022Mar 24, 2022Not reported
Industry KEV feedMar 3, 2022Mar 24, 2022Not reported
CIRCL KEVMar 3, 2022Mar 24, 2022Not reported
ENISA EUVDMar 3, 2022n/aNot reported

Required action: Apply updates per vendor instructions.

Affected Products

4 affected entries in total
ProductAffected versionsFixed in
IOSCisco>= 12.2(14)ZA12.4
IOS XeCiscoSee advisory3.17
Universal Product>= N/An/a

Patched Releases

IOS

12.4

IOS Xe

3.17

Timeline

  1. Publicly disclosed

    Jul 17, 2017

  2. Added to CISA KEV

    Mar 3, 2022

  3. Added to Industry KEV feed

    Mar 3, 2022

  4. Added to CIRCL KEV

    Mar 3, 2022

  5. Added to ENISA EUVD

    Mar 3, 2022

  6. Last updated

    Apr 21, 2026

Weakness Type

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

References

2 more references in the full CVE brief

FAQ

Common Questions.

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