8.6

CVE-2018-0173: Cisco IOS and IOS XE Software Improper Input Validation Vulnerability

CVSS: 8.6v3.1HighKEVAnalyzed
Published 28-03-2018Last modified 12-01-2026
Open JSON

Vulnerability summary

CVE-2018-0173 is a high (CVSS 8.6) Improper Input Validation vulnerability in Cisco IOS and IOS XE Software. It is known to be exploited: CISA lists it, first on 03-03-2022. EPSS estimates a 7.61% chance of exploitation in the next 30 days, higher than 94.5% of scored vulnerabilities.

Overall risk
85/100
0100
Critical · default modelHow is this calculated?
CVSS score
8.6/10
010
High · v3.1 (CVE.org)
EPSS score
7.61%
0%100%
Low · 0.00 pp in 30 days
KEVListedCISA
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 28-03-2018
    PublishedVulnerability first disclosed.
  2. 03-03-2022
    Added to CISA KEVCisco IOS and IOS XE Software Improper Input Validation Vulnerability
  3. 17-03-2022
    CISA remediation dueApply updates per vendor instructions.
  4. 12-01-2026
    Last modifiedVulnerability information updated.

Description

A vulnerability in the Cisco IOS Software and Cisco IOS XE Software function that restores encapsulated option 82 information in DHCP Version 4 (DHCPv4) packets could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a Relay Reply denial of service (DoS) condition. The vulnerability exists because the affected software performs incomplete input validation of encapsulated option 82 information that it receives in DHCPOFFER messages from DHCPv4 servers. An attacker could exploit this vulnerability by sending a crafted DHCPv4 packet to an affected device, which the device would then forward to a DHCPv4 server. When the affected software processes the option 82 information that is encapsulated in the response from the server, an error could occur. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvg62754.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

7.61%

Chance of exploitation in the next 30 days

Percentile

95%

Versus all other CVEs

30-day change

0.00 pp

From 7.61% on 19-09-2026

19-09-202619-10-2026
EPSS score
7.61%

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
03-03-2022
Federal due date
17-03-2022

CISA required action

Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2018-0173

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Cisco2 products
  • iosdenali-16.3.4 | ≤ 15.2\(6\)e0a | ≤ 15.2\(4a\)ea5
  • ios_xedenali-16.3.4 | ≤ 15.2\(6\)e0a | ≤ 15.2\(4a\)ea5

1 vendor · 2 products

References

7 links