CVEs / CVE-2018-0173
CVE-2018-0173: Cisco IOS and IOS XE Software Improper Input Validation Vulnerability
- Known exploited in the CISA KEV catalog since 3 Mar 2022
- high 8.6 CVSS 3.1 (NVD)
- EPSS 7.6% chance of exploitation in the next 30 days, higher than 94% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
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 can allow for denial-of-service (DoS).
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| n/a Cisco IOS and IOS XE | Cisco IOS and IOS XE | — |
Exploitation
| In CISA KEV since | 3 Mar 2022 |
|---|---|
| Due date for US federal agencies | 17 Mar 2022 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply updates per vendor instructions. |
Severity
| CVSS 3.1 | 8.6 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:HScored by NVD |
|---|---|
| Weakness | CWE-20 |
References
- CVE-2018-0173 on NVD
- CVE-2018-0173 in the CISA KEV catalog
- http://www.securityfocus.com/bid/103545 Broken Link, Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1040591 Broken Link, Third Party Advisory, VDB Entry
- https://ics-cert.us-cert.gov/advisories/ICSA-18-107-04 Third Party Advisory, US Government Resource
- https://ics-cert.us-cert.gov/advisories/ICSA-18-107-05 Third Party Advisory, US Government Resource
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-dhcpr2 Vendor Advisory
- https://www.tenable.com/security/research/tra-2018-06 Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0173 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.