CVE-2023-22411
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 Out-of-Bounds Write vulnerability in Flow Processing Daemon (flowd) of Juniper Networks Junos OS allows an unauthenticated, network-based attacker to cause Denial of Service (DoS). On SRX Series devices using Unified Policies with IPv6, when a specific IPv6 packet goes through a dynamic-application filter which will generate an ICMP deny message, the flowd core is observed and the PFE is restarted. This issue affects: Juniper Networks Junos OS on SRX Series: 19.2 versions prior to 19.2R3-S6; 19.3 versions prior to 19.3R3-S6; 19.4 versions prior to 19.4R3-S9; 20.2 versions prior to 20.2R3-S5; 20.3 versions prior to 20.3R3-S4; 20.4 versions prior to 20.4R3-S3; 21.1 versions prior to 21.1R3; 21.2 versions prior to 21.2R3; 21.3 versions prior to 21.3R2; 21.4 versions prior to 21.4R2.
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 confidenceAn out-of-bounds write vulnerability exists in the Flow Processing Daemon (flowd) of Juniper Junos OS on SRX Series devices. When Unified Policies are configured with IPv6 and a specific IPv6 packet traverses a dynamic-application filter that generates an ICMP deny message, it triggers an out-of-bounds write in flowd, causing the daemon to crash and restart the Packet Forwarding Engine (PFE), resulting in denial of service.
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= 19.2= 19.3= 19.4= 20.2= 20.3= 20.4= 21.1= 21.2= 21.3= 21.4CVSS 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.
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Verify device is SRX SeriesRun 'show chassis hardware' or 'show system information' to confirm the device model is an SRX Series device (SRX100, SRX210, SRX240, SRX340, SRX550, SRX1500, SRX4100, SRX4200, SRX5400, SRX5600, SRX5800, or vSRX)Affected if Device is not an SRX Series device - the vulnerability only affects SRX Series
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Confirm Junos OS version is affectedRun 'show version' and check if the installed Junos OS version matches 19.2, 19.3, 19.4, 20.2, 20.3, 20.4, 21.1, 21.2, 21.3, or 21.4Affected if Version is one of the listed affected versions in the CVE
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Check if Unified Policies with IPv6 are configuredRun 'show security policies detail' and look for policies with 'unified' or 'ipv6' in the output, or examine the configuration with 'show security policies' and look for policy-type unified with IPv6 address familiesAffected if Unified policies are configured with IPv6 - this is required for the vulnerability to be triggerable
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Check if dynamic-application filtering is enabled for IPv6Run 'show security application-filter' or review the security policy configuration for any dynamic-application-filter terms that apply to IPv6 trafficAffected if Dynamic-application filtering is applied to IPv6 traffic - the specific packet must traverse a dynamic-application filter that generates an ICMP deny message
A user is affected if they are running an affected Junos version on SRX Series hardware with Unified Policies configured that include IPv6 and have dynamic-application filtering enabled for IPv6 traffic that could generate ICMP deny messages.
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 patches for affected Junos OS versions (19.2R3-S6+, 19.3R3-S6+, 19.4R3-S9+, 20.2R3-S5+, 20.3R3-S4+, 20.4R3-S3+, 21.1R3+, 21.2R3+, 21.3R2+, 21.4R2+). As a interim mitigation, consider disabling IPv6 unified policies or blocking dynamic-application filtering for IPv6 traffic until patches can be deployed.
Upgrade to the fixed release for your branch: 19.2R3-S6/19.3R3-S6/19.4R3-S9/20.2R3-S5/20.3R3-S4/20.4R3-S3/21.1R3/21.2R3/21.3R2/21.4R2 or later
- Identify the current Junos OS version on the SRX Series device using 'show version'
- Determine the current branch (19.2, 19.3, 19.4, 20.2, 20.3, 20.4, 21.1, 21.2, 21.3, or 21.4) from the version output
- Download the appropriate fixed version for the branch from the Juniper support portal: 19.2R3-S6 or later, 19.3R3-S6 or later, 19.4R3-S9 or later, 20.2R3-S5 or later, 20.3R3-S4 or later, 20.4R3-S3 or later, 21.1R3 or later, 21.2R3 or later, 21.3R2 or later, 21.4R2 or later
- Upload the Junos upgrade package to the device using 'file copy' or USB storage
- Perform a system upgrade using 'request system software add <package> reboot' command
- Verify the upgrade completed successfully and the device is running the fixed version with 'show version'
- Confirm the Unified Policies with IPv6 functionality is working correctly after reboot
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2023-22411 — 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-2023-22411 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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