dbcve.org
Ios XrOperating system · Cisco

CVE-2025-20144

MEDIUM · 5.8 CVSS v3.1 Published 2025-03-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
Remediation priority · Elevated
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 hybrid access control list (ACL) processing of IPv4 packets in Cisco IOS XR Software could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to incorrect handling of packets when a specific configuration of the hybrid ACL exists. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass a configured ACL on the affected device. For more information, see the section of this advisory. Cisco has released software updates that address this vulnerability. There are 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 · moderate confidence

This vulnerability exists in Cisco IOS XR Software's hybrid access control list (ACL) processing for IPv4 packets. The flaw allows an unauthenticated remote attacker to bypass configured ACLs due to incorrect packet handling when a specific hybrid ACL configuration is present on the device.

MitigationApply the Cisco software updates that address this vulnerability or implement the available workarounds as specified in the Cisco advisory.

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:= 6.5.1= 6.5.2= 6.5.3= 6.5.92= 6.5.93= 6.6.1= 6.6.2= 6.6.3= 6.6.4= 6.6.25= 7.0.1= 7.0.2

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
Changed
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

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 the command 'show version' or 'admin show version' to display the installed IOS XR software version
    Affected if The displayed version matches one of these: 6.5.1, 6.5.2, 6.5.3, 6.5.92, 6.5.93, 6.6.1, 6.6.2, 6.6.3, 6.6.4, 6.6.25, 7.0.1, or 7.0.2
  2. Identify hybrid ACL configuration
    Run 'show access-lists' and examine the output for any access-list configurations that contain the 'hybrid' keyword. Alternatively, check configuration mode for 'ipv4 access-list' entries that include the 'hybrid' option by running 'show running-config | include hybrid'
    Affected if Any access-list entries with the 'hybrid' keyword are present in the configuration
  3. Verify hybrid ACL is applied to an interface
    Run 'show running-config interface' for relevant interfaces or use 'show ip interface' to see which interfaces have ACLs applied. Cross-reference with hybrid ACL names identified in the previous step
    Affected if A hybrid ACL is actively applied to one or more interfaces
  4. Confirm hybrid ACL handles IPv4 traffic
    Examine the hybrid ACL configuration details using 'show access-lists <acl-name>' to verify it contains ipv4 permit or deny rules and is used for inbound or outbound IPv4 packet filtering
    Affected if The applied hybrid ACL contains IPv4 packet filtering rules (permit/deny statements for IPv4 traffic)

The device is affected if it runs any of the listed affected IOS XR versions AND has a hybrid ACL configuration applied to interfaces for IPv4 packet filtering

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 software updates that address this vulnerability or implement the available workarounds as specified in the Cisco advisory.

Fix this in Ios Xr 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
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-20144 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2025-20144 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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