CVE-2020-3569: Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 3 Nov 2021, 406 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 3.3%
EPSS score, percentile 88.5 of all scored records
- How severe?
- 8.6 High
CVSS v3.1 base score, given by the CNA
- What should I do?
Required action (CISA), due 3 May 2022: Apply updates per vendor instructions.
- Which versions are affected?
Affected: unspecified
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
Apply updates per vendor instructions.
CISA due date for this action: 3 May 2022.
Advisories and patches
Linked from CISA's catalog entry
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | unspecified |
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
Cisco IOS XR Distance Vector Multicast Routing Protocol (DVMRP) incorrectly handles Internet Group Management Protocol (IGMP) packets. Exploitation could allow an unauthenticated, remote attacker to immediately crash the IGMP process or make it consume available memory and eventually crash.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2020-3569 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Nov 2021.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 3 May 2022.
- The CVE record was published on 23 Sep 2020, 406 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 8.6 (High), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 3.3% (percentile 88.5), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact partial.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerabilities
Multiple vulnerabilities in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to either immediately crash the Internet Group Management Protocol (IGMP) process or make it consume available memory and eventually crash. The memory consumption may negatively impact other processes that are running on the device. These vulnerabilities are due to the incorrect handling of IGMP packets. An attacker could exploit these vulnerabilities by sending crafted IGMP traffic to an affected device. A successful exploit could allow the attacker to immediately crash the IGMP process or cause memory exhaustion, resulting in other processes becoming unstable. These processes may include, but are not limited to, interior and exterior routing protocols. Cisco will release software updates that address these vulnerabilities.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 23 Sep 2020 | CVE record published |
| 3 Nov 2021 | Added to CISA KEV |
| 3 May 2022 | CISA due date for the required action |
| 21 Oct 2025 | CVE record last updated |
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