CVE-2024-21586
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 · uneditedAn Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on SRX Series and NFX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). If an affected device receives specific valid traffic destined to the device, it will cause the PFE to crash and restart. Continued receipt and processing of this traffic will create a sustained DoS condition. This issue affects Junos OS on SRX Series: * 21.4 versions before 21.4R3-S7.9, * 22.1 versions before 22.1R3-S5.3, * 22.2 versions before 22.2R3-S4.11, * 22.3 versions before 22.3R3, * 22.4 versions before 22.4R3. This issue affects Junos OS on NFX Series: * 21.4 versions before 21.4R3-S8, * 22.1 versions after 22.1R1, * 22.2 versions before 22.2R3-S5, * 22.3 versions before 22.3R3, * 22.4 versions before 22.4R3. Junos OS versions prior to 21.4R1 are not affected by this issue.
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 vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on SRX Series and NFX Series allows an unauthenticated, network-based attacker to crash and restart the PFE by sending specific valid traffic destined to the device. This creates a sustained DoS condition as the PFE continues to crash upon receiving the malicious traffic.
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= 21.4= 22.1= 22.2= 22.3= 22.4CVSS 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
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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.
-
Identify installed Junos OS versionExecute 'show version' or 'show version detail' on the device CLIAffected if The version output shows 21.4, 22.1, 22.2, 22.3, or 22.4 (any R variant within these branches)
-
Confirm device model is SRX or NFX SeriesExecute 'show chassis hardware' or 'show system information' to identify the hardware platformAffected if The device model is any SRX Series (SRX300, SRX340, SRX550, etc.) or NFX Series (NFX150, NFX250, NFX350, etc.)
-
Verify the device has active network interfaces accepting trafficExecute 'show interfaces terse' to confirm operational interfaces; check if the device is deployed as a border firewall with external-facing interfacesAffected if The device has operational network interfaces and processes traffic from untrusted networks (such as internet-facing or DMZ interfaces)
The device is affected if it runs Junos OS versions 21.4 through 22.4 on SRX or NFX Series hardware and has network-facing interfaces that can receive the malicious traffic pattern.
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.
dbcve · scopedApply the vendor-supplied Junos OS patches (21.4R3-S7.9, 22.1R3-S5.3, 22.2R3-S4.11, 22.3R3, 22.4R3 or later for respective branches) to resolve the improper check for unusual conditions in the PFE. Consider implementing firewall filters to block malicious traffic patterns as an interim measure.
Upgrade to the latest available release in your current version branch (e.g., 21.4R3-S7.9+, 22.1R3-S5.3+, 22.2R3-S4.11+, 22.3R3+, or 22.4R3+ for SRX; 21.4R3-S8+, 22.1R3-S5+, 22.2R3-S5+, 22.3R3+, or 22.4R3+ for NFX)
- Verify current Junos OS version on SRX Series or NFX Series devices using 'show version' command
- For SRX Series devices: upgrade to 21.4R3-S7.9 or later, 22.1R3-S5.3 or later, 22.2R3-S4.11 or later, 22.3R3 or later, or 22.4R3 or later depending on your current branch
- For NFX Series devices: upgrade to 21.4R3-S8 or later, 22.1R3-S5 or later, 22.2R3-S5 or later, 22.3R3 or later, or 22.4R3 or later depending on your current branch
- Download the appropriate upgrade package from the Juniper Networks support portal (supportportal.juniper.net)
- Upload the upgrade package to the device using 'file copy' or equivalent method
- Install the upgrade using 'request system software add <package-name>' command
- Reboot the device using 'request system reboot' command to complete the installation
- After reboot, verify the new version is installed using 'show version' and confirm the PFE is operational using 'show chassis fabric fpc' or equivalent commands
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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 locallyCheck whether your project pulls in CVE-2024-21586 — 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-2024-21586 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
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.
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.
- 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