CASCACascade Atlas

Evidence dossier

CVE-2018-0173

CVE-2018-0173

65.1–82.1Priority evidence range
As known Jul 19, 2026, 5:00 AM UTCgen-56ccdaf9

Normalized restatement

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.

State
PUBLISHED
Published
Mar 28, 2018
Updated
Jan 12, 2026
Evidence coverage
85%
CISA KEVCatalog member

Apply updates per vendor instructions.

FIRST EPSS7.76%

2026-07-18 · v2026.06.15 · percentile 94.0%

Source stateNo scored conflict

Distinct CVSS assessments remain side by side; none are averaged.

Source comparison

Who said what

CISA-ADPindependent enrichment
container

CISA ADP Vulnrichment

ciscooriginal assertion
container

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.

CVEderivative copy
container

CVE Program Container

CISA KEVoriginal assertion
observed_exploitation

Cisco IOS and IOS XE Software Improper Input Validation Vulnerability

FIRST EPSSoriginal assertion
model_probability

Probability 0.077580000000; percentile 0.939710000000

Applicability

Cited product scope

Trace impact →
n/aCisco IOS and IOS XE
[{"status": "affected", "version": "Cisco IOS and IOS XE"}]unknown
Unknown vendorUnknown product
cpe:2.3:h:cisco:4321_integrated_services_router:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:4331_integrated_services_router:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:4351_integrated_services_router:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:4431_integrated_services_router:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:4451-x_integrated_services_router:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_1000_series_route_processor_\(rp2\):-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_1000_series_route_processor_\(rp3\):-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_1001-hx:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_1001-x:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_1002-hx:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:asr_1002-x:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:cisco:cloud_services_router_1000v:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:rockwellautomation:allen-bradley_armorstratix_5700:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:rockwellautomation:allen-bradley_stratix_5400:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:rockwellautomation:allen-bradley_stratix_5410:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:rockwellautomation:allen-bradley_stratix_5700:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:rockwellautomation:allen-bradley_stratix_8000:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:h:rockwellautomation:allen-bradley_stratix_8300:-:*:*:*:*:*:*:*constrained
Unknown vendorUnknown product
cpe:2.3:o:cisco:ios:*:*:*:*:*:*:*:*; end including 15.2\(6\)e0asupported
Unknown vendorUnknown product
cpe:2.3:o:cisco:ios:*:*:*:*:*:*:*:*; end including 15.2\(4a\)ea5supported
Unknown vendorUnknown product
cpe:2.3:o:cisco:ios:denali-16.3.4:*:*:*:*:*:*:*supported
Unknown vendorUnknown product
cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:*; end including 15.2\(6\)e0asupported
Unknown vendorUnknown product
cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:*; end including 15.2\(4a\)ea5supported
Unknown vendorUnknown product
cpe:2.3:o:cisco:ios_xe:denali-16.3.4:*:*:*:*:*:*:*supported

Assessments

CVSS by origin

8.6
nvd@nist.govCVSS 3.1 · role PrimaryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
7.8
nvd@nist.govCVSS 2.0 · role PrimaryAV:N/AC:L/Au:N/C:N/I:N/A:C
8.6
134c704f-9b21-4f2e-91b3-4a467353bcc0CVSS 3.1 · role SecondaryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
8.6
CISA-ADPCVSS 3.1 · role unknownCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Limitations and unknowns

  • KEV membership is authoritative for the catalog, not proof of exposure in any environment.
  • EPSS is a dated model probability and not an individual-environment prediction.
  • Affected or fixed status applies only to the exact cited product and version scope; unresolved scope remains unknown.
  • NVD-carried upstream facts remain derivative and are not independent corroboration.
  • Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
  • NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
  • Factor D is unknown in Public Core because no accepted canonical mapping-obligation ledger is present.
  • Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.