CISA KEV · catalog date Mar 3, 2022 · first observed Jul 19, 2026
Evidence dossier
CVE-2018-0173
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…
Exploited in the wild (CISA KEV since Mar 3, 2022). NVD reports CVSS 3.1 8.6. EPSS estimates 7.7% exploit likelihood as of Aug 27, 2026.
As of Aug 27, 2026
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
- 97%
Evidence chronology
What was known when
- Source dateSource date omittedFirst observed by CASCACISA-ADPOriginal evidence ↗
Record text: CISA ADP Vulnrichment
Inspect raw assertion
- Field
container- Value
- CISA ADP Vulnrichment
- Source dateSource date omittedFirst observed by CASCAciscoOriginal evidence ↗
Record text: 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.
Inspect raw assertion
- Field
container- Value
- 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.
- Source dateSource date omittedFirst observed by CASCACVE ProgramOriginal evidence ↗
Record text: CVE Program Container
Inspect raw assertion
- Field
container- Value
- CVE Program Container
- Source dateFirst observed by CASCACISA KEVOriginal evidence ↗
Exploitation cataloged: Cisco IOS and IOS XE Software Improper Input Validation Vulnerability
Inspect raw assertion
- Field
observed_exploitation- Value
- Cisco IOS and IOS XE Software Improper Input Validation Vulnerability
- Source dateFirst observed by CASCAFIRST EPSSOriginal evidence ↗
EPSS score: 7.66% probability · 94.13th percentile
Inspect raw assertion
- Field
model_probability- Value
- Probability 0.076580000000; percentile 0.941330000000
FIRST EPSS · score date Aug 27, 2026 · 94.1th percentile · first observed Aug 27, 2026
NVD · CVSS 3.1 · first observed Jul 19, 2026 · same-version scores align in this snapshot
Evidence detail
Source limits and decisions
Why each evidence state has this value
casca-unknown-reasons-v1Eligible evidence is present for this bounded claim.
- Revision
- evidence-policy-v1.1.0
- Cutoff
- Aug 27, 2026
- Resolution
- None
Eligible evidence is present for this bounded claim.
- Revision
- evidence-policy-v1.1.0
- Cutoff
- Aug 27, 2026
- Resolution
- None
Eligible evidence is present for this bounded claim.
- Revision
- casca-direct-cvss-eligibility-v1
- Cutoff
- Aug 27, 2026
- Resolution
- None
The cited source assertion is retained while canonical product linkage remains open.
- Revision
- casca-factor-d-obligations-v1
- Cutoff
- Aug 27, 2026
- Resolution
- Resolve identity
Source comparison
Who said what
CISA ADP Vulnrichment
Inspect raw assertion
- Field
container- Value
- CISA ADP Vulnrichment
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.
Inspect raw assertion
- Field
container- Value
- 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.
CVE Program Container
Inspect raw assertion
- Field
container- Value
- CVE Program Container
Cisco IOS and IOS XE Software Improper Input Validation Vulnerability
Inspect raw assertion
- Field
observed_exploitation- Value
- Cisco IOS and IOS XE Software Improper Input Validation Vulnerability
7.66% probability · 94.13th percentile
Inspect raw assertion
- Field
model_probability- Value
- Probability 0.076580000000; percentile 0.941330000000
Applicability
Cited product scope
Grouped from 6 configuration nodes in this exact snapshot. Visual grouping is navigational; asset exposure and root cause require cited evidence.
Identity source boundaries
- Cpe dictionary1,775,266 records · observed through 2026-07-21T06:45:29.809Z
27d65b0f-b718-4b4f-bb79-c47c68d09dfa - Cpe match643,502 records · observed through 2026-07-21T08:13:17.697Z
955dae73-7302-438b-aee1-058d7cc5d48e
21 scope groups
Canonical linkage remains open; the cited source assertion is retained below.
Inspect raw assertion
[{"status": "affected", "version": "Cisco IOS and IOS XE"}]product-0ba2a993425c641e4c34302d679df853efcb7cb683154f3730e2fe3ed04586e6Linked exactInspect raw assertion
cpe:2.3:h:cisco:4321_integrated_services_router:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
9421dbef-ae42-4234-b49f-fcc34b804d7f
product-7c421c64ed9eb7859faef823f853ecdd6eb085833ac1be6bca2702863e075ff3Linked exactInspect raw assertion
cpe:2.3:h:cisco:4331_integrated_services_router:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
5419cb9f-241f-4431-914f-2659be27bea5
product-d2a1639dc1414e5bf3d96ae241a0ea96dadc1dbf3a4813e2e9f86ed908218557Linked exactInspect raw assertion
cpe:2.3:h:cisco:4351_integrated_services_router:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 2
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
7de02dbe-ead5-4f37-8ab7-df46a605a0e2
product-a8ab1568657db78724178da0f2ea1e511ac1672ed18fc30e12268df6f407ebaeLinked exactInspect raw assertion
cpe:2.3:h:cisco:4431_integrated_services_router:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 3
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
5720462a-be6b-4e84-a1a1-01e80bba86ad
product-6ee7be0ba4fa35532aaaf1221a35d683588441a8f8695c1d011248ab98ecf7d1Linked exactInspect raw assertion
cpe:2.3:h:cisco:4451-x_integrated_services_router:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 4
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
818cefa6-208c-43c3-8e43-474a93adcf21
product-5d9eb763f6a0bfd1f293363a5c5dd2edec76f7355e9eda5852969ea989b2b2b7Linked exactInspect raw assertion
cpe:2.3:h:cisco:asr_1000_series_route_processor_\(rp2\):-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 5
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
c02f9303-f9df-4166-ab4b-8c26b9fad109
product-d89fa88c2931411541a30e292c7af0ecd3c138681425b068ef882e3f97bb5984Linked exactInspect raw assertion
cpe:2.3:h:cisco:asr_1000_series_route_processor_\(rp3\):-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 6
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
372cb4d6-bb22-4521-9c18-c0a663717168
product-6ffe3f078b1fbff1bfaf1195da5632a15ea59dc998a11bf56f0b0bc98dea5ac5Linked exactInspect raw assertion
cpe:2.3:h:cisco:asr_1001-hx:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 7
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
7594e307-ac80-41ec-ae94-07e664a7d701
product-7d1996aa2655aeb23e3a03b6489799ad416e8aedbd6d10e55e901d21c5bdaad1Linked exactInspect raw assertion
cpe:2.3:h:cisco:asr_1001-x:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 8
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
09c913ff-63d5-43fb-8b39-598ef436ba5a
product-c0422ee07daa7be79700aded194408e1fc7fb1a9661a2d1d08c4d893f9c57ceaLinked exactInspect raw assertion
cpe:2.3:h:cisco:asr_1002-hx:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 9
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
cd2794bd-c8ce-46ef-9857-1723fcf04e46
product-7230cfe2ce5feb0072a6db1bfe3a1c9341bb2640d5c4a2f0f4778020fecd8ee3Linked exactInspect raw assertion
cpe:2.3:h:cisco:asr_1002-x:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 10
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
444f688f-79d0-4f22-b530-7bd520080b8f
product-8b7a877d68974249246d60580bde8aa549a5a0d87f250719631041cbf23a2578Linked exactInspect raw assertion
cpe:2.3:h:cisco:cloud_services_router_1000v:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 0 · node/1 · match 11
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
4ccb8270-a01d-40a6-bf4b-26baf65e68f3
product-5972f4392170d0d1b4e75a10eb3b383835ead601c8d9b09329525407a4e1471aLinked exactInspect raw assertions
cpe:2.3:o:cisco:ios:denali-16.3.4:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
c6efcb86-450d-4def-8010-3a7ca606899c
cpe:2.3:o:cisco:ios:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 2 · node/0 · match 0
- Logic
- OR
- Version bounds
- through including 15.2\(4a\)ea5
- Match ID
c7690ec4-f375-4d0a-8eed-26e01ecfde55
cpe:2.3:o:cisco:ios:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 1 · node/0 · match 0
- Logic
- OR
- Version bounds
- through including 15.2\(6\)e0a
- Match ID
aee6cc29-29a9-4465-b0ea-1ecc435ebc55
product-cc06181059d0f387414dd5737700c03a38fe93d65d4a541ac9744a37c25c9f59Linked exactInspect raw assertions
cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 1 · node/0 · match 1
- Logic
- OR
- Version bounds
- through including 15.2\(6\)e0a
- Match ID
dbbc562a-bc2c-4f64-b5d4-47c33bbee3c7
cpe:2.3:o:cisco:ios_xe:*:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 2 · node/0 · match 1
- Logic
- OR
- Version bounds
- through including 15.2\(4a\)ea5
- Match ID
c90778e3-4a55-498f-9cd6-80f8029aa722
cpe:2.3:o:cisco:ios_xe:denali-16.3.4:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Vulnerable target
- Configuration
- 0 · node/0 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
8654d912-c8ba-476e-a8ac-3c8c16fa655a
product-0ba0da2d834f87957eb2cbbe8af7841f85bd29dcc7b144dd62a938a904738cabLinked exactInspect raw assertion
cpe:2.3:h:rockwellautomation:allen-bradley_armorstratix_5700:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 1 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
d8849345-e011-4160-a91c-db760497af9a
product-711b032049212e8ff976133d7f8f20aec23230664475ea9b655ebccc5d41c46dLinked exactInspect raw assertion
cpe:2.3:h:rockwellautomation:allen-bradley_stratix_5400:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 1 · node/1 · match 1
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
de92939d-3d1e-445c-8888-f3eb4e35a034
product-e72ed84163580f65db57520117a86ed0e31a384d4f4e31881f6f6a03a4f1db25Linked exactInspect raw assertion
cpe:2.3:h:rockwellautomation:allen-bradley_stratix_5410:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 1 · node/1 · match 2
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
0b148d62-d1b2-4e40-9ddd-a8702dfad2e4
product-76672eb41960e7205c5e12de199412ca0600e80bd3c265e838644bb7593a9396Linked exactInspect raw assertion
cpe:2.3:h:rockwellautomation:allen-bradley_stratix_5700:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 1 · node/1 · match 3
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
8994dea7-c4ec-47b9-8aea-832af9d1f8e4
product-fbdfd1fd0d57143f69346d569adf8ea0acd2152416922dfa1455ed199d755fceLinked exactInspect raw assertion
cpe:2.3:h:rockwellautomation:allen-bradley_stratix_8000:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 1 · node/1 · match 4
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
f9a02987-e6f4-41d2-92c5-016a22ac7d0a
product-93072d5959f2cbb5479254c634f0df57f9e5d74e379076ba09fc46742636fcb7Linked exactInspect raw assertion
cpe:2.3:h:rockwellautomation:allen-bradley_stratix_8300:-:*:*:*:*:*:*:*- Official link
- Linked exact
- Role
- Environmental constraint
- Configuration
- 2 · node/1 · match 0
- Logic
- OR
- Version bounds
- No explicit bounds
- Match ID
3a97b3b5-6606-46f5-bcd8-141fdd6f6729
Affected-product evidence
Accepted scope and product mapping
2 canonical links · 1 source-reported links
vendor-0774b265c0e837e737aaf99ed0f2450c048e61f34267ca59d8623878b839334e · product-5972f4392170d0d1b4e75a10eb3b383835ead601c8d9b09329525407a4e1471a
- Source class
- Nvd cpe vulnerable target
- Assertions
- 3
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
50addf8b-bcf0-406f-a116-8795f015f1f06c71c742-567d-41e5-97d2-26aac0aa29369f0705f7-7771-4f7e-8571-f4f8ca205b48vendor-0774b265c0e837e737aaf99ed0f2450c048e61f34267ca59d8623878b839334e · product-cc06181059d0f387414dd5737700c03a38fe93d65d4a541ac9744a37c25c9f59
- Source class
- Nvd cpe vulnerable target
- Assertions
- 3
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
a86a00cd-1d70-4782-9eee-beccfe2971f5af0e5084-3049-4520-9ed4-1bc8a2fc742fe94c05a6-7551-4ed0-93b3-d212a50be712Canonical linkage remains open; the cited source assertion is retained below.
Vendor specified only by source · Product specified only by source
- Source class
- Direct cve affected
- Assertions
- 1
- Mapping revision
- cpe23-exact-mapping-v1
- Observed cutoff
- Aug 27, 2026
Retained assertion IDs
08e68d0e-32cf-4882-8b28-de0731b9c4d2Assessments
CVSS by origin
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:HAV:N/AC:L/Au:N/C:N/I:N/A:CCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:HCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:HDirect CVE/CNA normalized decisions
CISA-ADP
CVSS 3.1 · Secondary · Independent enrichment · rank 2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H- Validation
- Valid match
- Recomputed
- 8.6
- Decision reason
- Evidence supported
- Policy
- casca-direct-cvss-eligibility-v1
Assessments are retained side by side under closed precedence. Cascade never averages CVSS.
Evidence boundaries
- 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; remaining scope stays source-scoped.
- NVD-carried upstream facts remain derivative; independent corroboration requires a separately authored source.
- 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.
- Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.
- OSV aggregation and OSV-converted NVD material are not independent corroboration.
- Red Hat facts are vendor assertions for the exact supplied products.
- Nonmembership and not-yet-observed states are not proof of safety.