What it is
CVE-2018-0173 is an unauthenticated vulnerability affecting Cisco Cisco IOS and IOS XE. A vulnerability in the Cisco IOS Software and Cisco IOS XE Software function that restores encapsulated option 82 information in...
Vulnerability report
Exploited in the wild
Confirmed confidence
In CISA KEV
CVE-2018-0173
Cisco IOS and IOS XE Denial of Service
Cisco / Cisco IOS and IOS XE · Cisco IOS and IOS XE
- Severity
- CVSS 8.6 · High
- Confidence
- Confirmed
- Exploit status
- Exploited in the wild
- EPSS
- 7.7%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.
Who is affected?
Cisco / Cisco IOS and IOS XE cisco ios and ios xe.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
Cisco IOS and IOS XE Denial of Service
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.
Vendor
Product
Affected
Status
n/a
Cisco IOS and IOS XE
Cisco IOS and IOS XE
Affected
- Published
- 28 Mar 2018
- Exploitation Reported
- 03 Mar 2022
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- None
Tags
cisa
edge
ios
CVE References
- CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2018-0173
- 103545 securityfocus.com · VDB Entry http://www.securityfocus.com/bid/103545
- 1040591 securitytracker.com · VDB Entry http://www.securitytracker.com/id/1040591
- tools.cisco.com/security/center/content/CiscoSecurityAdvisor... tools.cisco.com · CVE Record https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory...
- ics-cert.us-cert.gov/advisories/ICSA-18-107-04 ics-cert.us-cert.gov · CVE Record https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04
- tenable.com/security/research/tra-2018-06 tenable.com · CVE Record https://www.tenable.com/security/research/tra-2018-06
- ics-cert.us-cert.gov/advisories/ICSA-18-107-05 ics-cert.us-cert.gov · CVE Record https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05
Exploitation evidence
Why KEV Intelligence marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
CISA
Independent exploitation attestation added to the KEV Intelligence record.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2022-03-03 00:00 UTC |
Detection
Operational artifacts and observed signals
Make the evidence actionable in scanner, SOC, and edge-control workflows.
Observed signals
- Request targets
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
No scanner integrations recorded yet.
Virtual patch status
No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.
Learn about virtual patches →No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Risk and context
Severity, weaknesses, and research context
CVSS v3.1
8.6
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS
7.7%
Weaknesses
All CVSS Scores
CVSS v3.1
8.6
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CVSS v2.0
7.8
High
AV:N/AC:L/Au:N/C:N/I:N/A:C
Timeline
From disclosure to observed exploitation
-
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
CVE published
Vulnerability disclosed publicly
-
CVE ID reserved
Identifier reserved by the CNA
Pro API
Automate this intelligence
Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
- Evidence confidence and provenance
- First-party sensor telemetry
- PoC and scanner references
- Affected versions and enrichment
- Automation-ready JSON delivery
GET /api/v2/pro/kevs/CVE-2018-0173
Free JSON includes basic KEV fields{
"cve_id": "CVE-2018-0173",
"confidence": "Confirmed",
"cvss_score": 8.6,
"cvss_estimated": false,
"epss_score": 0.07658,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}Early warning alerts
Get alerts on high-impact exploitation
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