CVE-2018-0026
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 · uneditedAfter Junos OS device reboot or upgrade, the stateless firewall filter configuration may not take effect. This issue can be verified by running the command: user@re0> show interfaces <interface_name> extensive | match filters" CAM destination filters: 0, CAM source filters: 0 Note: when the issue occurs, it does not show the applied firewall filter. The correct output should show the applied firewall filter, for example: user@re0> show interfaces <interface_name> extensive | match filters" CAM destination filters: 0, CAM source filters: 0 Input Filters: FIREWAL_FILTER_NAME-<interface_name> This issue affects firewall filters for every address family. Affected releases are Juniper Networks Junos OS: 15.1R4, 15.1R5, 15.1R6 and SRs based on these MRs. 15.1X8 versions prior to 15.1X8.3.
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 confidenceA bug in Junos OS causes stateless firewall filters to fail loading after device reboot or upgrade. The filters are configured but not applied to interfaces, showing 'CAM destination filters: 0, CAM source filters: 0' instead of the expected Input Filters entry. This leaves all traffic unfiltered when the device is in this state, effectively bypassing security policy.
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= 15.1= 15.1x8CVSS 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
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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 checksWork through these to decide whether this CVE applies to you.
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Check Junos OS versionRun 'show version' or 'show version detail' and note the software versionAffected if Version is 15.1 (any 15.1.x) or 15.1x8 (any 15.1x8.x)
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Verify firewall filter configuration existsRun 'show firewall' to confirm filters are configuredAffected if Filters show as configured but may not be applied
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Check interface filter application after reboot/upgradeRun 'show interfaces <interface_name> extensive | match filters' for each interface with a firewall filter appliedAffected if Output shows 'CAM destination filters: 0, CAM source filters: 0' or missing Input Filters entry instead of applied filter counts
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Cross-check with CAM filter utilizationRun 'show system camcmp' or 'show interface filters' to view CAM filter allocationAffected if CAM shows zero filters allocated despite firewall configuration existing
If running Junos 15.1 or 15.1x8 and interface filter checks show zero CAM filters after a reboot or upgrade, the device is affected by this CVE and traffic is bypassing security filters.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade Junos OS to version 15.1X8.3 or later (for 15.1X8 branch) or a fixed release beyond 15.1R6, then verify filter application using 'show interfaces <interface_name> extensive | match filters' after each reboot or upgrade.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-0026 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2018-0026 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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