dbcve.org
Ios XeOperating system · Cisco

CVE-2022-20678

HIGH · 7.5 CVSS v3.1 Published 2022-04-15
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 AppNav-XE feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of certain TCP segments. An attacker could exploit this vulnerability by sending a stream of crafted TCP traffic at a high rate through an interface of an affected device. That interface would need to have AppNav interception enabled. A successful exploit could allow the attacker to cause the device to reload.

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 confidence

A vulnerability in the AppNav-XE feature of Cisco IOS XE Software allows an unauthenticated, remote attacker to cause device reload via a denial of service condition. The flaw stems from incorrect handling of certain TCP segments when an attacker sends a high-rate stream of crafted TCP traffic through an interface that has AppNav interception enabled.

MitigationDisable AppNav interception on affected interfaces if possible, or apply Cisco's patch when available. Additionally, implement rate limiting or ACL filtering on suspicious TCP traffic to reduce exploitability while awaiting the official fix.

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 XeOperating system
Affected:= 16.9.6= 16.12.4= 16.12.5= 17.3.3

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. Identify the Cisco IOS XE version
    Run 'show version' on the device and locate the IOS XE release string (typically shows as Version 16.x.x, 17.x.x, etc.)
    Affected if The installed version matches 16.9.6, 16.12.4, 16.12.5, or 17.3.3 exactly
  2. Verify AppNav-XE feature is enabled
    Run 'show appnav status' or 'show feature | include appnav' to check if the AppNav-XE feature is active on the device
    Affected if AppNav-XE feature shows as enabled or running
  3. Check for AppNav interception configuration on interfaces
    Run 'show run | include appnav' or examine the running configuration for 'appnav intercept' commands applied to specific interfaces
    Affected if AppNav interception is configured on one or more interfaces (such as 'appnav intercept enable' or similar AppNav-related interface commands)
  4. Identify interfaces with AppNav interception active
    Run 'show appnav intercept status' or check individual interface configurations using 'show running-config interface <interface>' for interfaces with AppNav enabled
    Affected if Any interface has AppNav interception actively enabled and processing traffic

The device is affected if it runs IOS XE version 16.9.6, 16.12.4, 16.12.5, or 17.3.3 AND has AppNav-XE feature enabled with AppNav interception configured on one or more interfaces processing traffic.

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

Disable AppNav interception on affected interfaces if possible, or apply Cisco's patch when available. Additionally, implement rate limiting or ACL filtering on suspicious TCP traffic to reduce exploitability while awaiting the official fix.

Recommended fix Moderate confidence

Cisco IOS XE 17.4.1 (or later stable release); for 16.9.x branch upgrade to 16.9.7+, for 16.12.x upgrade to 16.12.6+, for 17.3.x upgrade to 17.4.1+

  1. 1. Identify all Cisco IOS XE devices running affected versions (16.9.6, 16.12.4, 16.12.5, 17.3.3) in the network inventory
  2. 2. Verify that AppNav interception is enabled on any interface by running 'show appnav stats' or 'show running-config | include appnav'
  3. 3. Schedule a maintenance window for the upgrade to minimize service impact
  4. 4. Download the Cisco IOS XE software upgrade image (recommended: 17.4.1 or later stable release for long-term support)
  5. 5. Back up the current device configuration using 'copy running-config startup-config' or 'copy running-config tftp://<server>'
  6. 6. Upgrade the device using 'archive download-sw /force-reload' or 'install' command appropriate to the platform
  7. 7. After reload, verify the new version using 'show version'
  8. 8. Confirm AppNav functionality is restored and check 'show appnav stats' for normal operation
Caveat Standard IOS XE upgrade risks apply - ensure configuration compatibility and test in lab before production deployment; some features may behave differently across major version branches

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

Fix this in Ios Xe Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2022-20678 in production — separate from our analysis above.

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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