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Ios XeOperating system · Cisco

CVE-2025-20162

HIGH · 8.6 CVSS v3.1 Published 2025-05-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
95/100
Remediation priority · Urgent
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 DHCP snooping security feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a full interface queue wedge, which could result in a denial of service (DoS) condition. This vulnerability is due to improper handling of DHCP request packets. An attacker could exploit this vulnerability by sending DHCP request packets to an affected device. A successful exploit could allow the attacker to cause packets to wedge in the queue, creating a DoS condition for downstream devices of the affected system and requiring that the system restart to drain the queue. Note: This vulnerability can be exploited with either unicast or broadcast DHCP packets on a VLAN that does not have DHCP snooping enabled.

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 XE's DHCP snooping feature allows unauthenticated remote attackers to send DHCP request packets that cause the interface queue to wedge (fill completely), creating a denial of service condition requiring system restart to recover. The vulnerability can be exploited via unicast or broadcast DHCP packets on VLANs where DHCP snooping is not enabled.

MitigationApply Cisco IOS XE software patches when available. As a mitigating control, enable DHCP snooping on vulnerable VLANs to reduce attack surface, though this may not fully address the underlying flaw in the DHCP snooping code 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 XeOperating system
Affected:= 16.11.1= 16.11.1a= 16.11.1s= 16.11.2= 16.12.1= 16.12.1a= 16.12.1c= 16.12.1s= 16.12.2= 16.12.2s= 16.12.3= 16.12.3s

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
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 checks

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

  1. Identify device platform and OS
    Run 'show version' or 'show inventory' to confirm the device runs Cisco IOS XE software and note the exact software version number
    Affected if Device runs any Cisco IOS XE version that matches 16.11.1 through 16.12.3s (or related 16.x variants)
  2. Verify IOS XE version against affected list
    Compare the installed version (from show version) against the affected versions: 16.11.1, 16.11.1a, 16.11.1s, 16.11.2, 16.12.1, 16.12.1a, 16.12.1c, 16.12.1s, 16.12.2, 16.12.2s, 16.12.3, 16.12.3s
    Affected if The installed IOS XE version exactly matches one of the listed affected versions
  3. Confirm DHCP snooping configuration
    Run 'show ip dhcp snooping' to check if DHCP snooping is globally enabled, and run 'show ip dhcp snooping vlan' to check per-VLAN status
    Affected if DHCP snooping is not enabled on the VLANs receiving DHCP traffic, or DHCP snooping is not configured at all on the device
  4. Check for interface queue behavior
    Monitor interface statistics using 'show interface <interface> statistics' or 'show platform hardware qfp active statistics drop' to look for unusual queue buildup or packet drops
    Affected if Interfaces show queue wedged or completely filled, especially on VLANs where DHCP traffic is processed and DHCP snooping is disabled

Device is affected if it runs any of the listed Cisco IOS XE versions AND DHCP snooping is not enabled on the VLANs where DHCP requests are received, allowing an attacker to fill the interface queue via DHCP packets.

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 Cisco IOS XE software patches when available. As a mitigating control, enable DHCP snooping on vulnerable VLANs to reduce attack surface, though this may not fully address the underlying flaw in the DHCP snooping code path.

Fix this in Ios Xe Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2025-20162 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