Security Resilience

CVE-2018-0174

Cisco Ios ≤ 15.2\(4a\)ea5

CISA KEVActive ExploitationEUVD Exploited
Published
28 March 2018
Modified
14 January 2026
KEV Added
03 March 2022
Patch / advisory
CVSS Score v3.1 8.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.076 94th percentile
Risk Priority 88 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-2018-0174 is a high-severity Improper Input Validation (CWE-20) vulnerability in Cisco Ios. Its CVSS base score is 8.6 (High).

Operationally, ranked in the top 6% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

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 DHCP option 82 encapsulation functionality of Cisco IOS Software and Cisco IOS XE Software due to incomplete input validation of option 82 information received in DHCPv4 packets from relay agents. The flaw, tracked under Cisco Bug ID CSCuh91645 and assigned CWE-20, permits an unauthenticated remote attacker to trigger a device reload by sending a specially crafted DHCPv4 packet, resulting in a denial-of-service condition. The issue carries a CVSS 3.1 base score of 8.6, reflecting network attack vector, low complexity, and high availability impact with changed scope.

An unauthenticated remote attacker can exploit the weakness by transmitting a crafted DHCPv4 packet containing malformed option 82 data toward an affected Cisco IOS or IOS XE device acting as a DHCP server or relay. Successful exploitation causes the device to reload, producing a denial-of-service condition without requiring authentication or user interaction.

Cisco has published Security Advisory cisco-sa-20180328-dhcpr3 along with related ICS-CERT advisories ICSA-18-107-04 and ICSA-18-107-05 that address the issue; additional details appear in SecurityFocus BID 103554 and SecurityTracker ID 1040591.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A vulnerability in the DHCP option 82 encapsulation functionality of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The…

more

vulnerability exists because the affected software performs incomplete input validation of option 82 information that it receives in DHCP Version 4 (DHCPv4) packets from DHCP relay agents. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCuh91645.

CWE(s)
KEV Date Added
03 March 2022

Related Threats

CVEs Like This One

CVE-2018-0172Same product: Cisco Iosboth on KEV
CVE-2018-0173Same product: Cisco Iosboth on KEV
CVE-2018-0175Same product: Cisco Iosboth on KEV
CVE-2018-0167Same product: Cisco Iosboth on KEV
CVE-2018-0158Same product: Cisco Iosboth on KEV
CVE-2018-0159Same 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-2017-12319Same product: Cisco Iosboth on KEV

Affected Assets

cisco
ios
12.2\(33\)sre7a · ≤ 15.2\(4a\)ea5 · ≤ 15.2\(6\)e0a
cisco
ios xe
12.2\(33\)sre7a · ≤ 15.2\(4a\)ea5 · ≤ 15.2\(6\)e0a

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