JunosOperating system · Juniper

CVE-2023-44204

MEDIUM · 6.5 CVSS v3.1 Published 2023-10-13

Mitigation only

No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.

See remediation →

70/100

Remediation priority · Elevated

No privileges Zero-click

Official description

NVD · unedited

An Improper Validation of Syntactic Correctness of Input vulnerability in Routing Protocol Daemon (rpd) Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network based attacker to cause a Denial of Service (DoS). When a malformed BGP UPDATE packet is received over an established BGP session, the rpd crashes and restarts. This issue affects both eBGP and iBGP implementations. This issue affects: Juniper Networks Junos OS * 21.4 versions prior to 21.4R3-S4; * 22.1 versions prior to 22.1R3-S3; * 22.2 versions prior to 22.2R3-S2; * 22.3 versions prior to 22.3R2-S2, 22.3R3; * 22.4 versions prior to 22.4R2-S1, 22.4R3; * 23.2 versions prior to 23.2R1, 23.2R2; Juniper Networks Junos OS Evolved * 21.4 versions prior to 21.4R3-S5-EVO; * 22.1 versions prior to 22.1R3-S3-EVO; * 22.2 versions prior to 22.2R3-S3-EVO; * 22.3 versions prior to 22.3R2-S2-EVO; * 22.4 versions prior to 22.4R3-EVO; * 23.2 versions prior to 23.2R2-EVO;

Technical summary

dbcve analysis · high confidence

A malformed BGP UPDATE packet received on an established BGP session causes the rpd (routing protocol daemon) to crash and restart due to improper validation of syntactic correctness of input in the BGP packet parser, resulting in denial of service for both eBGP and iBGP implementations.

MitigationApply the vendor-supplied patches for Junos OS or Junos OS Evolved corresponding to the affected version; as a temporary mitigation, implement BGP packet filtering at network boundaries to reject malformed UPDATE messages.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions

NVD · CPE data

JunosOperating system

Affected:= 21.4= 22.1= 22.2= 22.3= 22.4

Junos Os EvolvedOperating system

Affected:= 21.4= 22.1= 22.2= 22.3= 22.4= 23.2

CVSS breakdown

From the vector

Attack vector: Adjacent
Complexity: Low
Privileges: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected?

dbcve checks

Work through these to decide whether this CVE applies to you.

Identify Junos version

Run 'show version' or 'show version detail' on the device CLI to obtain the installed Junos version

Affected if The version matches 21.4, 22.1, 22.2, 22.3, 22.4 (Junos) or 21.4, 22.1, 22.2, 22.3, 22.4, 23.2 (Junos OS Evolved)
Confirm BGP is configured

Run 'show bgp summary' or 'show configuration protocols bgp' to determine if BGP is actively configured on the device

Affected if BGP is enabled and peers are configured (either eBGP or iBGP)
Check rpd crash history

Run 'show system core-dumps' and review system logs for rpd crash events using 'show log messages | match rpd' or 'show log messages | match crash'

Affected if Recent rpd crashes are present in logs or core dumps exist for the rpd process
Inspect BGP peer status

Run 'show bgp neighbor' to examine the state of BGP peers and look for frequent session resets or unexpected down events

Affected if BGP sessions are dropping or restarting unexpectedly without explicit administrative action
Review BGP UPDATE message parsing

If possible, capture BGP traffic with 'monitor traffic interface' or use external packet capture to verify if malformed UPDATE messages are being received

Affected if Malformed BGP UPDATE packets are being received on any BGP session

A device is affected if it runs a matched Junos version, has BGP enabled, and is receiving malformed BGP UPDATE packets that could trigger rpd crashes.

Generated from the published advisory. Verify against your own configuration.

Remediation

dbcve · scoped

Mitigation available No clean upgrade yet — mitigate in the meantime

Mitigation

Apply the vendor-supplied patches for Junos OS or Junos OS Evolved corresponding to the affected version; as a temporary mitigation, implement BGP packet filtering at network boundaries to reject malformed UPDATE messages.

Recommended fix High confidence

Upgrade to the appropriate fixed release: Junos OS 21.4R3-S4/22.1R3-S3/22.2R3-S2/22.3R2-S2/22.3R3/22.4R2-S1/22.4R3/23.2R1/23.2R2, or Junos OS Evolved 21.4R3-S5-EVO/22.1R3-S3-EVO/22.2R3-S3-EVO/22.3R2-S2-EVO/22.4R3-EVO/23.2R2-EVO

1. Identify the exact Junos OS or Junos OS Evolved version currently running using 'show version' command
2. Determine the appropriate fixed release based on your current branch (21.4, 22.1, 22.2, 22.3, 22.4, or 23.2)
3. For Junos OS: upgrade to 21.4R3-S4, 22.1R3-S3, 22.2R3-S2, 22.3R2-S2/22.3R3, 22.4R2-S1/22.4R3, or 23.2R1/23.2R2 as appropriate
4. For Junos OS Evolved: upgrade to 21.4R3-S5-EVO, 22.1R3-S3-EVO, 22.2R3-S3-EVO, 22.3R2-S2-EVO, 22.4R3-EVO, or 23.2R2-EVO as appropriate
5. Download the Junos upgrade package from the Juniper Networks support portal
6. Follow standard Junos upgrade procedures: copy the package to the device, run 'request system software add <package>', and reboot
7. After upgrade, verify the rpd process is running with 'show chassis routing-engine' and confirm BGP peers are established

Caveat Standard Junos upgrade precautions apply: ensure configuration backup, verify hardware compatibility, plan maintenance window as upgrade will cause routing disruption

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

Fix this in Junos Scoped from the published advisory

Consultation4.0 h
Implementation8.0 h
Testing6.0 h
Review / QA2.0 h

20.0 hours of engineering $3,500

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References

Primary sources

supportportal.juniper.netVendor Advisory
nvd.nist.govNVD record

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-44204 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2023-44204?

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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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

At a glance

A fix existsA vendor remedy is published

Severity 6.5 Medium

Exploit likelihood EPSS, next 30 days 0.3%

Affects: Junos

Remediation

Need this fixed?

Fix this in Junos 20 hrs · Moderate

Typical engagement from $3,500

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You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References