dbcve.org
Ios XrOperating system · Cisco

CVE-2024-20317

HIGH · 7.4 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 →
79/100
Remediation priority · High
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 handling of specific Ethernet frames by Cisco IOS XR Software for various Cisco Network Convergence System (NCS) platforms could allow an unauthenticated, adjacent attacker to cause critical priority packets to be dropped, resulting in a denial of service (DoS) condition. This vulnerability is due to incorrect classification of certain types of Ethernet frames that are received on an interface. An attacker could exploit this vulnerability by sending specific types of Ethernet frames to or through the affected device. A successful exploit could allow the attacker to cause control plane protocol relationships to fail, resulting in a DoS condition. For more information, see the section of this advisory. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

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

A vulnerability in Cisco IOS XR Software on NCS platforms allows an unauthenticated, adjacent attacker to cause critical priority packets to be dropped by sending specific Ethernet frames that are incorrectly classified. This misclassification leads to control plane protocol failures and denial of service.

MitigationApply the Cisco software updates for IOS XR Software on affected NCS platforms. No workarounds are available, so updating is the only remediation path.

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= 7.8.22= 7.9.1= 7.9.2= 7.9.21= 7.10.1

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/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 checks

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

  1. Identify the hardware platform
    Run 'show platform' or 'show inventory' to confirm the device is an NCS platform (NCS-5500, NCS-5700, NCS-540, etc.)
    Affected if The device is an NCS platform from Cisco
  2. Check the IOS XR version
    Run 'show version' and locate the IOS XR software version string (e.g., Version 7.10.1)
    Affected if The installed version matches exactly 7.7.1, 7.7.2, 7.7.21, 7.8.1, 7.8.2, 7.8.22, 7.9.1, 7.9.2, 7.9.21, or 7.10.1
  3. Verify Ethernet interfaces are present
    Run 'show ip interface brief' or 'show interface description' to list active Ethernet interfaces
    Affected if Ethernet interfaces are configured and active on the device
  4. Confirm control plane protocols are running
    Run 'show protocols' to verify if OSPF, BGP, or other control plane protocols are active
    Affected if Control plane protocols are enabled and running on the device

A user is affected if the device is an NCS platform running exactly one of the listed IOS XR versions (7.7.1 through 7.10.1) and has active Ethernet interfaces with control plane protocols in use.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco software updates for IOS XR Software on affected NCS platforms. No workarounds are available, so updating is the only remediation path.

Recommended fix Moderate confidence

Upgrade to the next available maintenance release in your current branch (e.g., 7.7.3 or later for 7.7.x, or 7.8.2 or later for 7.8.x) or migrate to a later stable release as specified in the Cisco security advisory

  1. 1. Identify the current Cisco IOS XR version running on the affected NCS platform using 'show version' command
  2. 2. Confirm the specific NCS platform model (e.g., NCS-5500, NCS-5700 series) to ensure compatibility
  3. 3. Contact Cisco TAC or check the official Cisco Security Advisory (cisco.com) for the exact fixed version corresponding to your current release branch
  4. 4. Download the fixed IOS XR software version from Cisco's Software Download center
  5. 5. Plan maintenance window as this upgrade will require a reload of the device
  6. 6. Backup current configuration using 'admin commit backup' or 'copy running-config startup-config'
  7. 7. Install the fixed IOS XR release using the 'install' command or via ROMMON if needed
  8. 8. After upgrade, verify the system is operational and confirm the new version with 'show version'
Caveat Standard IOS XR upgrade risks apply: requires reload, verify compatibility with other network elements, test in lab first if possible

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ios Xr Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,280
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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-2024-20317 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data