Security Resilience

CVE-2017-3881

Cisco Ios 12.2s – 15.1\(3\)svs

CISA KEVActive ExploitationEUVD ExploitedPublic PoC
Published
17 March 2017
Modified
22 April 2026
KEV Added
25 March 2022
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.99 99.9th percentile
Risk Priority 97 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2017-3881 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Cisco Ios. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 0.1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A vulnerability exists in the Cisco Cluster Management Protocol (CMP) processing code within Cisco IOS and Cisco IOS XE Software. The flaw stems from the protocol's use of Telnet for internal signaling between cluster members combined with a failure to restrict CMP-specific Telnet options to local communications and incorrect handling of malformed options. It affects a range of devices including Catalyst switches, IE Industrial Ethernet switches, ME 4924-10GE switches, RF Gateway 10, and multiple EtherSwitch service modules. The issue is tracked as Cisco Bug ID CSCvd48893 and carries a CVSS score of 9.8.

An unauthenticated remote attacker can exploit the vulnerability by initiating a Telnet session to an affected device configured to accept Telnet connections and sending specially crafted CMP-specific Telnet options. Successful exploitation grants the attacker the ability to execute arbitrary code with elevated privileges, resulting in full device control, or to trigger a reload that causes a denial of service.

The referenced Cisco Security Advisory cisco-sa-20170317-cmp along with associated security bulletins from SecurityFocus, SecurityTracker, and Exploit-DB entry 41872 provide details on available patches and workarounds. Public exploit code has been published, indicating that the issue is reproducible outside of controlled environments.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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.…

more

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.

CWE(s)
KEV Date Added
25 March 2022

Related Threats

CVEs Like This One

CVE-2018-0156Same product: Cisco Catalyst 2960-Plus 24Lc-Lboth on KEV
CVE-2018-0159Same product: Cisco Iosboth on KEV
CVE-2017-12319Same product: Cisco Iosboth on KEV
CVE-2017-12235Same product: Cisco Iosboth on KEV
CVE-2017-12234Same product: Cisco Iosboth on KEV
CVE-2017-12233Same product: Cisco Iosboth on KEV
CVE-2018-0125Same vendor: Ciscoboth on KEV
CVE-2009-2055Same vendor: Ciscoboth on KEV
CVE-2025-20393Same vendor: Ciscoboth on KEV
CVE-2020-3161Same vendor: Ciscoboth on KEV

Affected Assets

cisco
ios
12.2s — 15.1\(3\)svs
cisco
ios xe
3.2sg — 3.9e

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

blocks

A.8.25 mandates security requirements, secure coding guidelines, checkpoints, testing (incl. code scans) and developer training in the SDLC, which reaches a slice of input validation defects but leaves the majority (incomplete enforcement, second-order inputs, parser differentials, post-validation canonicalization) unaddressed as in the SA-3 and A.8.28 anchors.

blocks

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

blocks

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-20, a class-level weakness, and none of its children carries one either.

References