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ExploitedIn CISA KEVFix available

CVE-2020-3118

Exploitation confirmed. First attested on 2021-11-03 by CISA-ADP, CISA KEV, GCVE · kevintel.

  • Published2020-02-05
  • Fixed in7.0.2 · 6.6.12
  • WeaknessCWE-134 · CWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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).

Timeline

dates in UTC
  1. 2020-02-0518:15CVE publishedNVD
  2. 2021-11-03Added to the CISA KEV catalogCISA KEV
  3. 2021-11-03Listed as exploited by GCVEGCVE
  4. 2021-11-03Exploitation first reportedCISA KEV
  5. 2024-11-0816:12SSVC exploitation set to activeCISA-ADP

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-3118?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-3118?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Cisco ios xrversion to verify
BranchAffectedFixed in
7.0≥ 7.0.0, < 7.0.27.0.2
6.6≥ 6.6.0, < 6.6.126.6.12
6.5= 6.5.3no fix published
5.2= 5.2.5no fix published
6.4= 6.4.2no fix published
6.6= 6.6.25no fix published
7.0= 7.0.1no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As cisco, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Cisco IOS XR Software
    Affected
    • < 6.6.3fixed in 6.6.3custom

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2020-02-05

Fix

  1. Update Cisco ios xr to 7.0.2 · 6.6.12
  2. CISA’s required action: Apply updates per vendor instructions.due 2022-05-03

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

CISA Known Exploited Vulnerability

Date Added
2021-11-03
Patch Due Date
2022-05-03
Ransomware Use
Unknown
Required Action
Apply updates per vendor instructions.

Sources

  • CISA KEVKEV entry2021-11-03
  • ENISA EUVDexploitation2021-11-032021-11-03
  • GCVEexploitation2021-11-03
  • CISA-ADPSSVC decisionactive2024-11-08
  • OpenCVESSVC decisionactive—
  • NVDCVSS 3.18.8read 2026-10-23
  • CNACVSS 3.08.8known since 2026-10-23
  • NVDCVSS 2.08.3read 2026-10-23
  • CNAweakness (CWE)CWE-134known since 2026-10-23
  • NVDweakness (CWE)CWE-787read 2026-10-23
  • FIRST EPSSEPSS score11.7 %read 2026-11-03
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2020-02-05
Last Modified
2026-06-17
NVD status
Analyzed
GitHub Advisory
GHSA-f7vj-6cqm-9xgc

Frequently asked questions

What is CVE-2020-3118?

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).

Is CVE-2020-3118 actively exploited?

Yes. CVE-2020-3118 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2022-05-03.

What is the CVSS score for CVE-2020-3118?

CVE-2020-3118 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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