CVE-2017-6739
HighExploitedPublic exploitA 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.
Published Jul 17, 2017 · Updated Apr 22, 2026
Key Facts
Patch immediately- CVE-2017-6739 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 3.17.0.
- 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-2017-6739 brief as a PDF
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Description
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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Mar 3, 2022 | Mar 24, 2022 | Not reported |
| Industry KEV feed | Mar 3, 2022 | Mar 24, 2022 | Not reported |
| CIRCL KEV | Mar 3, 2022 | Mar 24, 2022 | Not reported |
| ENISA EUVD | Mar 3, 2022 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
3 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| IOSCisco | See advisory | 12.4 |
| IOS XeCisco | See advisory | 3.17.0 |
| Universal Product | >= N/A | n/a |
Patched Releases
IOS
12.4
IOS Xe
3.17.0
Timeline
Publicly disclosed
Jul 17, 2017
Added to CISA KEV
Mar 3, 2022
Added to Industry KEV feed
Mar 3, 2022
Added to CIRCL KEV
Mar 3, 2022
Added to ENISA EUVD
Mar 3, 2022
Last updated
Apr 22, 2026
Weakness Type
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
References
- advisorycisco-sa-20170629-snmp
- advisoryhttps://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20170629-snmp
- advisory99345
- advisory1038808
- exploitVulnCheck exploitation report
FAQ
Common Questions.
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.
Affected: IOS (Cisco); IOS Xe (Cisco); Universal Product versions >= N/A. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 3, 2022.
Yes. It was added on Mar 3, 2022 with a federal remediation due date of Mar 24, 2022.
Public exploit code is available.
Fixed versions are available, including IOS 12.4, IOS Xe 3.17.0.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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