Evidence dossier

CVE-2020-3118

Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability

67.6–83.8Priority evidence range

As known Jul 19, 2026, 5:00 AM UTCgen-56ccdaf9

Normalized restatement

A vulnerability in the Cisco Discovery Protocol implementation for Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to execute arbitrary code or cause a reload on an affected device. The vulnerability is due to improper validation of string input from certain fields in Cisco Discovery Protocol messages. An attacker could exploit this vulnerability by sending a malicious Cisco Discovery Protocol packet to an affected device. A successful exploit could allow the attacker to cause a stack overflow, which could allow the attacker to execute arbitrary code with administrative privileges on an affected device. Cisco Discovery Protocol is a Layer 2 protocol. To exploit this vulnerability, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).

State: PUBLISHED
Published: Feb 5, 2020
Updated: Oct 21, 2025
Evidence coverage: 85%

CISA KEVCatalog member

Apply updates per vendor instructions.

FIRST EPSS11.68%

2026-07-18 · v2026.06.15 · percentile 95.6%

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

Jul 19, 2026Original evidence ↗

ciscooriginal assertion

container

Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability

Jul 19, 2026Original evidence ↗

CVEderivative copy

container

CVE Program Container

Jul 19, 2026Original evidence ↗

CISA KEVoriginal assertion

observed_exploitation

Cisco IOS XR Software Discovery Protocol Format String Vulnerability

Jul 19, 2026Original evidence ↗

FIRST EPSSoriginal assertion

model_probability

Probability 0.116850000000; percentile 0.955920000000

Jul 19, 2026Original evidence ↗

Applicability

Cited product scope

Trace impact →

CiscoCisco IOS XR Software

[{"status": "affected", "version": "unspecified", "lessThan": "6.6.3", "versionType": "custom"}]unknown

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9000:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9000v:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9000v:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9001:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9001:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9006:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9006:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9010:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9010:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9901:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9901:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9903:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9904:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9904:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9906:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9906:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9910:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9910:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9912:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9912:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9920:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9922:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:asr_9922:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:crs-x:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540-12z20g-sys-a:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540-12z20g-sys-d:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540-24z8q2c-sys:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540-28z4c-sys-a:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540-28z4c-sys-d:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540-acc-sys:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540l:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540x-12z16g-sys-a:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540x-12z16g-sys-d:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540x-16z4g8q2c-a:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540x-16z4g8q2c-d:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_540x-acc-sys:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_5501:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_5501-se:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_5502:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_5502-se:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_5508:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_5516:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_560:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_6000:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:ncs_6008:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:h:cisco:xrv_9000:-:*:*:*:*:*:*:*constrained

Unknown vendorUnknown product

cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*; start including 6.6.0; end excluding 6.6.12supported

Unknown vendorUnknown product

cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*; start including 7.0.0; end excluding 7.0.2supported

Unknown vendorUnknown product

cpe:2.3:o:cisco:ios_xr:5.2.5:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:cisco:ios_xr:6.4.2:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:cisco:ios_xr:6.5.3:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:cisco:ios_xr:6.6.25:*:*:*:*:*:*:*supported

Unknown vendorUnknown product

cpe:2.3:o:cisco:ios_xr:7.0.1:*:*:*:*:*:*:*supported

Assessments

CVSS by origin

8.8

nvd@nist.govCVSS 3.1 · role PrimaryCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

8.3

nvd@nist.govCVSS 2.0 · role PrimaryAV:A/AC:L/Au:N/C:C/I:C/A:C

8.8

psirt@cisco.comCVSS 3.0 · role SecondaryCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

8.8

ciscoCVSS 3.0 · role unknownCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.