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PatchSiren cyber security CVE debrief

CVE-2020-3569 Cisco CVE debrief

CVE-2020-3569 is a Cisco IOS XR Software DVMRP memory exhaustion vulnerability that CISA added to its Known Exploited Vulnerabilities catalog on 2021-11-03. Because it is identified as a known exploited issue, affected Cisco IOS XR environments should be prioritized for remediation according to vendor guidance and internal change procedures.

Vendor
Cisco
Product
IOS XR
CVSS
HIGH 8.6
CISA KEV
Listed
Original CVE published
2021-11-03
Original CVE updated
2021-11-03
Advisory published
2021-11-03
Advisory updated
2021-11-03

Who should care

Cisco IOS XR operators, especially network teams managing multicast or DVMRP-related configurations, should care most. Security operations, vulnerability management, and patch/change management teams should also treat this as a high-priority remediation item because CISA has flagged it as known exploited.

Technical summary

The supplied official records identify the issue as a Cisco IOS XR Software DVMRP memory exhaustion vulnerability. CISA’s KEV entry marks it as a known exploited vulnerability and directs organizations to apply updates per vendor instructions. The supplied corpus does not include a CVSS score or deeper exploit details, so this debrief limits itself to the official classification and response guidance.

Defensive priority

High. CISA has listed CVE-2020-3569 in the Known Exploited Vulnerabilities catalog, which means defenders should treat it as an active risk and move remediation ahead of routine backlog work.

Recommended defensive actions

  • Identify Cisco IOS XR assets in scope and confirm whether DVMRP-related features or configurations are present.
  • Prioritize vendor-recommended updates or mitigations for affected systems.
  • Track remediation through change management, especially for infrastructure that carries multicast or routing traffic.
  • Validate post-update device stability and monitor for abnormal memory behavior or service disruption.
  • Use the CISA KEV catalog entry as a trigger to verify exposure and completion status across the fleet.

Evidence notes

All statements are grounded in the supplied official corpus: the CISA KEV record names the issue as a Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability, marks it as known exploited, and specifies the response guidance to apply updates per vendor instructions. The timeline supplied by the prompt sets the CVE published and modified dates, as well as the KEV date added, to 2021-11-03. No CVSS score or additional technical specifics were provided in the corpus.

Sources and references

Verified primary and authoritative sources

  • CVE-2020-3569 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2020-3569

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2020-3569 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2020-3569

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.