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Nx OsOperating system · Cisco

CVE-2017-3875

MEDIUM · 5.3 CVSS v3.0 Published 2017-03-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
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
An Access-Control Filtering Mechanisms Bypass vulnerability in certain access-control filtering mechanisms on Cisco Nexus 7000 Series Switches could allow an unauthenticated, remote attacker to bypass defined traffic configured within an access control list (ACL) on the affected system. More Information: CSCtz59354. Known Affected Releases: 5.2(4) 6.1(3)S5 6.1(3)S6 6.2(1.121)S0 7.2(1)D1(1) 7.3(0)ZN(0.161) 7.3(1)N1(0.1). Known Fixed Releases: 7.3(0)D1(1) 6.2(2) 6.1(5) 8.3(0)KMT(0.24) 8.3(0)CV(0.337) 7.3(1)N1(1) 7.3(0)ZN(0.210) 7.3(0)ZN(0.177) 7.3(0)ZD(0.194) 7.3(0)TSH(0.99) 7.3(0)SC(0.14) 7.3(0)RSP(0.7) 7.3(0)N1(1) 7.3(0)N1(0.193) 7.3(0)IZN(0.13) 7.3(0)IB(0.102) 7.3(0)GLF(0.44) 7.3(0)D1(0.178) 7.1(0)D1(0.14) 7.0(3)ITI2(1.6) 7.0(3)ISH1(2.13) 7.0(3)IFD6(0.78) 7.0(3)IFD6(0) 7.0(3)IDE6(0.12) 7.0(3)IDE6(0) 7.0(3)I2(1) 7.0(3)I2(0.315) 7.0(1)ZD(0.3) 7.0(0)ZD(0.84) 6.2(1.149)S0 6.2(0.285) 6.1(5.32)S0 6.1(4.97)S0 6.1(2.30)S0.

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

This vulnerability allows an unauthenticated remote attacker to bypass configured Access Control Lists (ACLs) on Cisco Nexus 7000 Series Switches. The ACL filtering mechanism can be circumvented, permitting traffic that should be blocked to pass through the affected system.

MitigationApply the appropriate fixed software release from the known fixed releases list (e.g., 6.1(5), 6.2(2), 7.0(3)I2(1), or later) after proper assessment and planning.

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
Nx OsOperating system
Affected:= 5.2\(4\)= 6.1\(3\)s5= 6.1\(3\)s6= 6.2\(1.121\)s0= 7.2\(1\)d1\(1\)= 7.3\(0\)zn\(0.161\)= 7.3\(1\)n1\(0.1\)

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/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. Identify the device model
    Run 'show version' or 'show inventory' to confirm the device is a Cisco Nexus 7000 Series Switch
    Affected if Device is not a Cisco Nexus 7000 Series Switch (this CVE only applies to that platform)
  2. Check NX-OS version
    Run 'show version' and locate the 'NX-OS' or 'system' version line. Compare against these affected versions: 5.2(4), 6.1(3)s5, 6.1(3)s6, 6.2(1.121)s0, 7.2(1)d1(1), 7.3(0)zn(0.161), 7.3(1)n1(0.1)
    Affected if The installed NX-OS version matches exactly one of the listed affected versions
  3. Verify ACLs are configured
    Run 'show ip access-lists summary' or 'show running-config | include ip access-list' to check for configured Access Control Lists
    Affected if No ACLs are configured - the vulnerability only affects systems with ACLs in place
  4. Check ACL application points
    Run 'show vlan access-map' for VACLs, 'show ip interface' for RACLs on SVI interfaces, or 'show port-channel summary' for PACLs to see where ACLs are applied
    Affected if ACLs exist in configuration but are not applied to any interfaces (the bypass requires active ACL enforcement)

A user is affected if they are running a Cisco Nexus 7000 Series Switch with NX-OS version matching one of the affected versions AND they have ACLs configured and applied to interfaces or VLANs.

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 appropriate fixed software release from the known fixed releases list (e.g., 6.1(5), 6.2(2), 7.0(3)I2(1), or later) after proper assessment and planning.

Fix this in Nx Os Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,980
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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-2017-3875 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