Ios XrOperating system · Cisco
CVE-2020-3569
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedMultiple 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceMultiple vulnerabilities in the DVMRP feature of Cisco IOS XR Software allow an unauthenticated remote attacker to crash the IGMP process or cause memory exhaustion by sending crafted IGMP packets. The memory consumption destabilizes other processes including interior and exterior routing protocols.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Ios XrOperating system
= 6.1.4= 6.2.3= 6.3.3= 6.4.2= 6.5.3= 6.6.2= 6.6.3= 7.0.2= 7.1.2= 7.1.15< 6.5.2= 6.4.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the Cisco IOS XR versionRun 'show version' on the device CLI to display the installed software versionAffected if The version matches any of these: 6.1.4, 6.2.3, 6.3.3, 6.4.2, 6.5.3, 6.6.2, 6.6.3, 7.0.2, 7.1.2, 7.1.15, 6.4.3, or any version below 6.5.2 (such as 6.5.1, 6.5.0, 6.4.x below 6.4.2, 6.3.x, 6.2.x, 6.1.x)
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Verify if DVMRP is enabledRun 'show running-config | include dvmrp' or 'show dvmrp interface' to check if DVMRP is configured on any interfaceAffected if DVMRP is actively configured or running on the device, making it susceptible to crafted IGMP packets
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Confirm IGMP is configuredRun 'show igmp interface' or 'show running-config | include igmp' to check IGMP statusAffected if IGMP is enabled and processing multicast traffic, which is required for the vulnerability to be exploitable
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Check for IGMP process instabilityRun 'show processes igmp' or 'show log | include IGMP' to look for recent crashes, restarts, or memory alerts related to the IGMP processAffected if The IGMP process has recently crashed, restarted repeatedly, or shows abnormal memory consumption
The device is affected if it runs a vulnerable IOS XR version (6.1.4, 6.2.3, 6.3.3, 6.4.2, 6.5.3, 6.6.2, 6.6.3, 7.0.2, 7.1.2, 7.1.15, < 6.5.2, or 6.4.3) AND has DVMRP and IGMP enabled, allowing unauthenticated IGMP traffic to trigger the vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped6.5.2
Apply Cisco software updates addressing these vulnerabilities; until patches are available, implement network segmentation to limit exposure to untrusted IGMP sources and consider IGMP access control lists on adjacent devices to filter malicious traffic.
Specific fixed release varies by IOS XR train; consult Cisco Security Advisory cisco-sa-iosxr-igmp-dvmrp-XzNhXy3A for version details
- 1. Identify the current Cisco IOS XR version using 'show version' command
- 2. Contact Cisco support or check Cisco's Security Advisories page (tools.cisco.com) for the specific fixed release for your IOS XR version
- 3. Download the appropriate fixed IOS XR software release from Cisco's software download center
- 4. Plan maintenance window as upgrade will require device reload
- 5. Backup current configuration using 'admin commit backup' or 'copy running-config startup-config'
- 6. Upload new IOS XR image to device bootflash
- 7. Set new boot image using 'boot system bootflash:<new-image-name>'
- 8. Reload the device using 'reload' command
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Ios Xr
Exploited in the wild — priority engagement
- Consultation3.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-3569 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-3569 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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