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OpenstackApplication · Redhat

CVE-2017-7543

MEDIUM · 5.9 CVSS v3.0 Published 2018-07-26
Fix available
A fix is available. Upgrade to 7.2.0-12.1 / 8.3.0-11.1 or later.
See remediation →
68/100
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 race-condition flaw was discovered in openstack-neutron before 7.2.0-12.1, 8.x before 8.3.0-11.1, 9.x before 9.3.1-2.1, and 10.x before 10.0.2-1.1, where, following a minor overcloud update, neutron security groups were disabled. Specifically, the following were reset to 0: net.bridge.bridge-nf-call-ip6tables and net.bridge.bridge-nf-call-iptables. The race was only triggered by an update, at which point an attacker could access exposed tenant VMs and network resources.

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 race-condition flaw in OpenStack Neutron (versions before 7.2.0-12.1, 8.x before 8.3.0-11.1, 9.x before 9.3.1-2.1, and 10.x before 10.0.2-1.1) causes security groups to be disabled following a minor overcloud update. The vulnerability specifically resets net.bridge.bridge-nf-call-ip6tables and net.bridge.bridge-nf-call-iptables to 0, disabling the iptables-based filtering that enforces neutron security group rules.

MitigationUpgrade neutron to the patched versions (7.2.0-12.1, 8.3.0-11.1, 9.3.1-2.1, or 10.0.2-1.1 or later). After any overcloud update, verify that the bridge-nf-call-iptables values remain at 1 and that security groups are functioning correctly.

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
OpenstackApplication
Affected:= 6.0= 7.0= 8= 9= 10= 11
NeutronApplication
Affected:>= 7.0.0, < 7.2.0-12.1>= 8.0.0, < 8.3.0-11.1>= 9.0.0, < 9.3.1-2.1>= 10.0.0, < 10.0.2-1.1

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/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 installed Neutron version
    Run 'neutron --version' or check the Neutron package version using your package manager (e.g., 'rpm -q neutron' on RHEL-based systems)
    Affected if The version falls within any of these ranges: >= 7.0.0 and < 7.2.0-12.1, >= 8.0.0 and < 8.3.0-11.1, >= 9.0.0 and < 9.3.1-2.1, or >= 10.0.0 and < 10.0.2-1.1
  2. Verify bridge-nf-call-iptables sysctl value
    Run 'sysctl net.bridge.bridge-nf-call-iptables' to check the current value
    Affected if The value is 0, indicating iptables filtering for IPv4 is disabled
  3. Verify bridge-nf-call-ip6tables sysctl value
    Run 'sysctl net.bridge.bridge-nf-call-ip6tables' to check the current value
    Affected if The value is 0, indicating iptables filtering for IPv6 is disabled
  4. Confirm security group enforcement is disabled
    Create a security group rule blocking ingress traffic, attach a port with that security group, and attempt to reach the port from another instance to verify the rule is enforced
    Affected if Traffic is allowed when the security group rule should block it, indicating security groups are not functioning

You are affected if you run a vulnerable Neutron version AND either bridge-nf-call-iptables or bridge-nf-call-ip6tables is set to 0, which disables security group enforcement.

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
Upgrade available Upgrade to 7.2.0-12.1 / 8.3.0-11.1 / 9.3.1-2.1 or later
Fixed in 7.2.0-12.18.3.0-11.19.3.1-2.1
Interim mitigation

Upgrade neutron to the patched versions (7.2.0-12.1, 8.3.0-11.1, 9.3.1-2.1, or 10.0.2-1.1 or later). After any overcloud update, verify that the bridge-nf-call-iptables values remain at 1 and that security groups are functioning correctly.

Fix this in Openstack Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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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-2017-7543 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