CVE-2017-3881

9.8 CRITICAL 99% exploit odds Drop everything exploited in the wild Fix listed Code execution Network gear

What it is

A vulnerability in the Cisco Cluster Management Protocol (CMP) processing code in Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a reload of an affected device or remotely execute code with elevated privileges. The Cluster Management Protocol utilizes Telnet internally as a signaling and command protocol between cluster members. The vulnerability is due to the combination of two factors: (1) the failure to restrict the use of CMP-specific Telnet options only to internal, local communications between cluster members and instead accept and process such options over any Telnet connection to an affected device; and (2) the incorrect processing of malformed CMP-specific Telnet options. An attacker could exploit this vulnerability by sending malformed CMP-specific Telnet options while establishing a Telnet session with an affected Cisco device configured to accept Telnet connections. An exploit could allow an attacker to execute arbitrary code and obtain full control of the device or cause a reload of the affected device. This affects Catalyst switches, Embedded Service 2020 switches, Enhanced Layer 2 EtherSwitch Service Module, Enhanced Layer 2/3 EtherSwitch Service Module, Gigabit Ethernet Switch Module (CGESM) for HP, IE Industrial Ethernet switches, ME 4924-10GE switch, RF Gateway 10, and SM-X Layer 2/3 EtherSwitch Service Module. Cisco Bug IDs: CSCvd48893.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
In the wild: CISA lists this as exploited in real attacks. Treat as urgent.
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2016-12-21 00:00 UTC ReservedThe CVE id was reserved by its CNA
2017-03-17 22:59 UTC PublishedDisclosed publicly on CVE.org and NVD
2022-03-25 Exploited in the wildAdded to CISA's Known Exploited Vulnerabilities list
2022-04-15 Remediation deadlineCISA's due date for federal agencies to fix it
2026-06-17 01:19 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: yes, CISA lists it. This puts it above everything that is not.
Exploit odds: 99.0% in the next 30 days (EPSS).
Severity: 9.8 CRITICAL (CVSS).
Fix: a patch or advisory is linked.
It meets the bar for Drop everything: critical, and exploited or very likely to be.

Details

Published: 2017-03-17 22:59 UTC
Last modified: 2026-06-17 01:19 UTC
Added to CISA KEV: 2022-03-25
Exploit probability: 99.0% · EPSS, next 30 days
Weakness: CWE-20 · Improper input validation
Record status: Analyzed

Affected

Cisco iOS ≤ 15.1\(3\)svs
Cisco iOS Xe ≤ 3.9e

Attack profile CVSS 3.1 · 9.8

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

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

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record