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JunosOperating system · Juniper

CVE-2024-30405

HIGH · 7.5 CVSS v3.1 Published 2024-04-12
Fix available
A fix is available. Upgrade to 21.2 or later.
See remediation →
84/100
Remediation priority · High
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 Incorrect Calculation of Buffer Size vulnerability in Juniper Networks Junos OS SRX 5000 Series devices using SPC2 line cards while ALGs are enabled allows an attacker sending specific crafted packets to cause a transit traffic Denial of Service (DoS). Continued receipt and processing of these specific packets will sustain the Denial of Service condition. This issue affects: Juniper Networks Junos OS SRX 5000 Series with SPC2 with ALGs enabled. * All versions earlier than 21.2R3-S7; * 21.4 versions earlier than 21.4R3-S6; * 22.1 versions earlier than 22.1R3-S5; * 22.2 versions earlier than 22.2R3-S3; * 22.3 versions earlier than 22.3R3-S2; * 22.4 versions earlier than 22.4R3; * 23.2 versions earlier than 23.2R2.

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

An incorrect buffer size calculation in the ALG (Application Layer Gateway) processing path on Juniper SRX 5000 Series devices with SPC2 line cards allows remote attackers sending specially crafted packets to cause a denial of service by disrupting transit traffic processing.

MitigationApply the appropriate Junos OS version update per the version matrix (21.2R3-S7 and later, 21.4R3-S6 and later, 22.1R3-S5 and later, 22.2R3-S3 and later, 22.3R3-S2 and later, 22.4R3 and later, or 23.2R2 and later). As a compensating control, disable unused ALGs if the upgrade cannot be performed immediately.

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
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 checks

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

  1. Identify device model
    Run 'show chassis hardware' or 'show system information' to confirm the device is an SRX 5000 Series model
    Affected if Device is NOT an SRX 5000 Series device (the vulnerability only affects this series)
  2. Verify SPC2 line card presence
    Run 'show chassis hardware detail' or 'show chassis fpc' to check for SPC2 line cards in the device
    Affected if Device does NOT have SPC2 line cards (the flaw requires SPC2 line cards)
  3. Check Junos OS version
    Run 'show version' or 'show system information' to obtain the installed Junos version
    Affected if Version matches: < 21.2, = 21.2, = 21.4, = 22.1, = 22.2, = 22.3, = 22.4, or = 23.2 (any of these vulnerable versions)
  4. Verify ALG modules are enabled
    Run 'show security alg' to list enabled Application Layer Gateway modules
    Affected if ANY ALG is enabled (the buffer size calculation flaw occurs in the ALG processing path, so enabled ALGs create the attack surface)

User is affected if the device is an SRX 5000 Series with SPC2 line cards, runs a vulnerable Junos version listed above, and has at least one ALG module enabled.

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

Apply the appropriate Junos OS version update per the version matrix (21.2R3-S7 and later, 21.4R3-S6 and later, 22.1R3-S5 and later, 22.2R3-S3 and later, 22.3R3-S2 and later, 22.4R3 and later, or 23.2R2 and later). As a compensating control, disable unused ALGs if the upgrade cannot be performed immediately.

Recommended fix High confidence

Upgrade to 21.2R3-S7 or later (21.4R3-S6, 22.1R3-S5, 22.2R3-S3, 22.3R3-S2, 22.4R3, or 23.2R2 depending on your release train)

  1. 1. Identify the current Junos OS version running on the SRX 5000 Series device with SPC2 line cards using 'show version'
  2. 2. Confirm ALGs are enabled by checking the configuration with 'show configuration security alg'
  3. 3. Download the appropriate fixed Junos OS version from Juniper Networks support portal based on the current version branch
  4. 4. Upload the Junos OS upgrade package to the device using 'file copy' or FTP/SCP
  5. 5. Install the upgrade using 'request system software add <package-name> reboot'
  6. 6. After reboot, verify the new version with 'show version' and confirm ALG functionality with 'show security alg status'
  7. 7. Test transit traffic flows to verify DoS condition is resolved
Caveat Standard Junos upgrade precautions apply - test in lab first, ensure configuration backup, plan for brief outage during reboot

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

Fix this in Junos Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2024-30405 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data