CVE DATABASE / CVE-2017-3881

CVE-2017-3881

Cisco IOS and IOS XE Remote Code Execution Vulnerability

CVSS 9.8 · CRITICAL ⚠ CISA KEV — ACTIVELY EXPLOITED

On the CISA KEV catalog

Confirmed exploited in the wild. Added 2022-03-25. Federal remediation due 2022-04-15.
Required action: Apply updates per vendor instructions.

Summary

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.

CVSS 3.1 breakdown

Base score	9.8 (CRITICAL)
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector	NETWORK
Attack complexity	LOW
Privileges required	NONE
User interaction	NONE
Scope	UNCHANGED
Confidentiality	HIGH
Integrity	HIGH
Availability	HIGH

Weakness type (CWE)

CWE-20

Affected products

Cisco iosCisco ios xeCisco catalyst 2350-48td-sCisco catalyst 2350-48td-sdCisco catalyst 2360-48td-sCisco catalyst 2918-24tc-cCisco catalyst 2918-24tt-cCisco catalyst 2918-48tc-cCisco catalyst 2918-48tt-cCisco catalyst 2928-24tc-cCisco catalyst 2960-24-sCisco catalyst 2960-24lc-sCisco catalyst 2960-24lt-lCisco catalyst 2960-24pc-lCisco catalyst 2960-24pc-sCisco catalyst 2960-24tc-lCisco catalyst 2960-24tc-sCisco catalyst 2960-24tt-lCisco catalyst 2960-48pst-lCisco catalyst 2960-48pst-s

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References

Data: NIST NVD + CISA KEV. NVD last modified 2026-04-22. Always verify against the vendor advisory before acting.