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JunosOperating system · Juniper

CVE-2024-39533

MEDIUM · 5.8 CVSS v3.1 Published 2024-07-11
Fix available
A fix is available. Upgrade to 21.2 or later.
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
An Unimplemented or Unsupported Feature in the UI vulnerability in Juniper Networks Junos OS on QFX5000 Series and EX4600 Series allows an unauthenticated, network-based attacker to cause a minor integrity impact to downstream networks.If one or more of the following match conditions ip-source-address ip-destination-address arp-type which are not supported for this type of filter, are used in an ethernet switching filter, and then this filter is applied as an output filter, the configuration can be committed but the filter will not be in effect. This issue affects Junos OS on QFX5000 Series and EX4600 Series: * All version before 21.2R3-S7,  * 21.4 versions before 21.4R3-S6, * 22.1 versions before 22.1R3-S5, * 22.2 versions before 22.2R3-S3, * 22.3 versions before 22.3R3-S2,  * 22.4 versions before 22.4R3, * 23.2 versions before 23.2R2. Please note that the implemented fix ensures these unsupported match conditions cannot be committed anymore.

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 unsupported match conditions (ip-source-address, ip-destination-address, arp-type) to be configured in ethernet switching filters applied as output filters on QFX5000 and EX4600 Series devices. The configuration commits successfully but the filter silently fails to function, creating a false sense of security where network operators believe traffic is being filtered when it is not.

MitigationUpgrade to a fixed Junos OS version (21.2R3-S7, 21.4R3-S6, 22.1R3-S5, 22.2R3-S3, 22.3R3-S2, 22.4R3, or 23.2R2 or later). Audit existing filter configurations to ensure no unsupported match conditions are in use for ethernet switching output filters.

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
JunosOperating system
Affected:< 21.2= 21.2= 21.4= 22.1= 22.2= 22.3= 22.4= 23.2

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. Confirm device model is vulnerable hardware
    Run 'show chassis hardware' or check the device model via 'show system information' to verify the hardware is a QFX5000 Series or EX4600 Series switch
    Affected if Device model is QFX5000 or EX4600 series
  2. Check Junos OS version against affected releases
    Run 'show version' to obtain the Junos OS version and compare against the affected list: < 21.2, 21.2, 21.4, 22.1, 22.2, 22.3, 22.4, 23.2
    Affected if Junos version matches any version in the affected list
  3. Identify ethernet switching output filters
    Run 'show configuration firewall family ethernet-switching' and look for filter terms applied with 'then' action containing 'accept' or 'discard' in the output direction. Alternatively, run 'show configuration class-of-service interfaces' if filters are applied as output filters there
    Affected if Any ethernet-switching family filters exist with output-direction application
  4. Inspect filter terms for unsupported match conditions
    Within each ethernet-switching output filter, examine the 'from' statements for any of these three match conditions: 'ip-source-address', 'ip-destination-address', or 'arp-type'. Run 'show configuration firewall family ethernet-switching filter <filter-name> | display set' for detailed term configuration
    Affected if Any of the three unsupported match conditions (ip-source-address, ip-destination-address, or arp-type) are present in filters applied as output filters on ethernet-switching family

A user is affected if they run a vulnerable Junos version on QFX5000 or EX4600 hardware AND have ethernet-switching output filters containing ip-source-address, ip-destination-address, or arp-type match conditions, as these filters will silently fail to filter traffic.

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.

dbcve · scoped
Upgrade available Upgrade to 21.2 or later
Fixed in 21.2
Interim mitigation

Upgrade to a fixed Junos OS version (21.2R3-S7, 21.4R3-S6, 22.1R3-S5, 22.2R3-S3, 22.3R3-S2, 22.4R3, or 23.2R2 or later). Audit existing filter configurations to ensure no unsupported match conditions are in use for ethernet switching output filters.

Recommended fix High confidence

Upgrade to 21.2R3-S7 or later (21.2 branch), 21.4R3-S6 or later (21.4 branch), 22.1R3-S5 or later (22.1 branch), 22.2R3-S3 or later (22.2 branch), 22.3R3-S2 or later (22.3 branch), 22.4R3 or later (22.4 branch), or 23.2R2 or later (23.2 branch)

  1. 1. Identify the current Junos OS version and branch running on the affected QFX5000 Series or EX4600 Series device using 'show version'
  2. 2. Determine the appropriate upgrade path based on the current branch (21.2, 21.4, 22.1, 22.2, 22.3, 22.4, or 23.2)
  3. 3. Review any existing ethernet switching filters configured on the device using 'show configuration' under the relevant firewall filter hierarchy
  4. 4. Identify any filters that use unsupported match conditions (ip-source-address, ip-destination-address, or arp-type) applied as output filters on ethernet switching interfaces
  5. 5. Remove or modify these unsupported filter configurations before upgrading, as they cannot be committed in fixed versions
  6. 6. Download the appropriate fixed Junos OS release for the device model from the Juniper Networks support portal
  7. 7. Upload the software package to the device and perform the upgrade following standard Junos OS upgrade procedures
  8. 8. After upgrade, verify that the previously unsupported match conditions are now properly rejected at commit time
Caveat Review firewall filter configurations before upgrade - filters using unsupported match conditions will fail to commit after upgrade; test upgrade in lab environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Junos Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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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-2024-39533 in production — separate from our analysis above.

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