dbcve.org
Ios XrOperating system · Cisco

CVE-2024-20304

HIGH · 7.5 CVSS v3.1 Published 2024-09-11
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

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 · unedited
A vulnerability in the multicast traceroute version 2 (Mtrace2) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to exhaust the UDP packet memory of an affected device. This vulnerability exists because the Mtrace2 code does not properly handle packet memory. An attacker could exploit this vulnerability by sending crafted packets to an affected device. A successful exploit could allow the attacker to exhaust the incoming UDP packet memory. The affected device would not be able to process higher-level UDP-based protocols packets, possibly causing a denial of service (DoS) condition. Note: This vulnerability can be exploited using IPv4 or IPv6.

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 · high confidence

The Mtrace2 feature in Cisco IOS XR Software contains a memory handling flaw where crafted UDP packets (IPv4 or IPv6) can cause unbounded memory allocation. An unauthenticated remote attacker sending specially constructed packets can exhaust the device's incoming UDP packet memory buffer, preventing processing of other UDP-based protocols and causing a denial of service.

MitigationApply the Cisco IOS XR Software patch or upgrade to a fixed version as specified in the Cisco security advisory. If immediate patching is not possible, consider disabling the Mtrace2 feature if not required in production.

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
Affected:= 7.7.1= 7.7.2= 7.7.21= 7.8.1= 7.8.2= 7.8.12= 7.8.22= 7.9.1= 7.9.2= 7.9.21= 7.10.1= 7.10.2

CVSS 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
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check Cisco IOS XR version
    Run 'show version' on the device CLI and locate the IOS XR release version in the output (typically shown as something like 7.x.x)
    Affected if The installed version matches one of the affected versions: 7.7.1, 7.7.2, 7.7.21, 7.8.1, 7.8.2, 7.8.12, 7.8.22, 7.9.1, 7.9.2, 7.9.21, 7.10.1, or 7.10.2
  2. Verify Mtrace2 feature configuration
    Run 'show running-config | include mtrace' to check if Mtrace2 (multicast traceroute) is configured on the device
    Affected if Mtrace2 is enabled or configured (the feature responds to UDP packets on port 65404 by default when enabled)
  3. Check for UDP buffer exhaustion indicators
    Run 'show buffers' or 'show memory summary' to inspect UDP buffer utilization and overall memory status
    Affected if UDP buffer pool shows high utilization or near exhaustion, particularly for incoming packets
  4. Monitor for Mtrace2 UDP traffic
    Use 'show udp statistics' or packet capture on the device to observe incoming UDP traffic patterns on port 65404 (Mtrace2 default port)
    Affected if Large volumes of incoming UDP packets to port 65404 are observed, especially from untrusted sources

You are affected if your device runs an IOS XR version in the list AND the Mtrace2 feature is enabled, making it susceptible to UDP-based memory exhaustion attacks.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco IOS XR Software patch or upgrade to a fixed version as specified in the Cisco security advisory. If immediate patching is not possible, consider disabling the Mtrace2 feature if not required in production.

Fix this in Ios Xr Scoped from the published advisory
  • Consultation4.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,300
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-20304 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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