Is CVE-2017-12240 in the CISA KEV catalog?

Yes. CVE-2017-12240 is on the CISA Known Exploited Vulnerabilities list, added 2022-03-03.

What is the CVSS severity of CVE-2017-12240?

CVE-2017-12240 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2017-12240?

CVE-2017-12240 has an EPSS score of 13.52% (96th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2017-12240

CRITICALCISA KEVEPSS 96th pctl

9.8

CVSS v3

NVD

Description

The DHCP relay subsystem of Cisco IOS 12.2 through 15.6 and Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code and gain full control of an affected system. The attacker could also cause an affected system to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to a buffer overflow condition in the DHCP relay subsystem of the affected software. An attacker could exploit this vulnerability by sending a crafted DHCP Version 4 (DHCPv4) packet to an affected system. A successful exploit could allow the attacker to execute arbitrary code and gain full control of the affected system or cause the affected system to reload, resulting in a DoS condition. Cisco Bug IDs: CSCsm45390, CSCuw77959.

CWE-20Improper Input Validation CWE-119Buffer Overflow

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

13.52%probability of exploitation in 30 days

96thpercentile

Very high risk: more likely to be exploited than 96% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Cisco IOS and IOS XE Software DHCP Remote Code Execution Vulnerability

The Dynamic Host Configuration Protocol (DHCP) relay subsystem of Cisco IOS and Cisco IOS XE Software contains a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code and gain full control of an affected system.

Apply updates per vendor instructions.

Remediation due: 2022-03-24

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-21.