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JunosOperating system · Juniper

CVE-2024-21594

MEDIUM · 5.5 CVSS v3.1 Published 2024-01-12
Fix available
A fix is available. Upgrade to 20.4 or later.
See remediation →
57/100
Remediation priority · Elevated
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
A Heap-based Buffer Overflow vulnerability in the Network Services Daemon (NSD) of Juniper Networks Junos OS allows authenticated, low privileged, local attacker to cause a Denial of Service (DoS). On an SRX 5000 Series device, when executing a specific command repeatedly, memory is corrupted, which leads to a Flow Processing Daemon (flowd) crash. The NSD process has to be restarted to restore services. If this issue occurs, it can be checked with the following command: user@host> request security policies check The following log message can also be observed: Error: policies are out of sync for PFE node<number>.fpc<number>.pic<number>. This issue affects: Juniper Networks Junos OS on SRX 5000 Series * All versions earlier than 20.4R3-S6; * 21.1 versions earlier than 21.1R3-S5; * 21.2 versions earlier than 21.2R3-S4; * 21.3 versions earlier than 21.3R3-S3; * 21.4 versions earlier than 21.4R3-S3; * 22.1 versions earlier than 22.1R3-S1; * 22.2 versions earlier than 22.2R3; * 22.3 versions earlier than 22.3R2.

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

Heap-based buffer overflow in Juniper NSD (Network Services Daemon) on SRX 5000 Series allows authenticated low-privileged local attacker to corrupt memory via repeated execution of a specific command, causing flowd crash and DoS. The NSD process must be restarted to restore services.

MitigationUpgrade Junos OS to fixed versions (20.4R3-S6, 21.1R3-S5, 21.2R3-S4, 21.3R3-S3, 21.4R3-S3, 22.1R3-S1, 22.2R3, 22.3R2 or later). Until patched, monitor for policy sync errors and be prepared to restart NSD if DoS occurs.

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:< 20.4= 20.4= 21.1= 21.2= 21.3= 21.4= 22.1= 22.2= 22.3

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 the device model
    Run 'show chassis hardware' or 'show system information' to confirm the device is an SRX 5000 Series model
    Affected if The device is NOT an SRX 5000 Series (the vulnerability only affects SRX 5000 Series)
  2. Check the Junos OS version
    Run 'show version' to obtain the installed Junos OS version
    Affected if The installed version matches one of the affected versions: < 20.4, 20.4, 21.1, 21.2, 21.3, 21.4, 22.1, 22.2, or 22.3
  3. Verify NSD is running
    Run 'show system processes' or 'request system process' to confirm the Network Services Daemon (nsd) process is active
    Affected if NSD is running (the vulnerability exploits the NSD process)
  4. Check for flowd crashes or NSD restarts
    Run 'show log messages' and search for 'flowd' or 'nsd' crash entries, or use 'request system core-dumps' to list any recent core dumps
    Affected if Recent flowd or NSD crash events are present in logs or core dumps exist
  5. Look for policy sync errors
    Run 'show security policies' and check 'show log messages' for policy sync failure errors
    Affected if Policy sync errors are appearing, which may indicate exploitation in progress

The device is affected if it is an SRX 5000 Series running a Junos version in the affected list and either NSD crashes or policy sync errors are observed.

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 20.4 or later
Fixed in 20.4
Interim mitigation

Upgrade Junos OS to fixed versions (20.4R3-S6, 21.1R3-S5, 21.2R3-S4, 21.3R3-S3, 21.4R3-S3, 22.1R3-S1, 22.2R3, 22.3R2 or later). Until patched, monitor for policy sync errors and be prepared to restart NSD if DoS occurs.

Recommended fix High confidence

20.4R3-S6, 21.1R3-S5, 21.2R3-S4, 21.3R3-S3, 21.4R3-S3, 22.1R3-S1, 22.2R3, or 22.3R2 (depending on which release train you are on)

  1. 1. Identify the current Junos OS version running on the SRX 5000 Series device using the command: show version
  2. 2. Based on the current version, determine the appropriate upgrade path to a fixed release:
  3. - If on 20.4.x: Upgrade to 20.4R3-S6 or later
  4. - If on 21.1.x: Upgrade to 21.1R3-S5 or later
  5. - If on 21.2.x: Upgrade to 21.2R3-S4 or later
  6. - If on 21.3.x: Upgrade to 21.3R3-S3 or later
  7. - If on 21.4.x: Upgrade to 21.4R3-S3 or later
  8. - If on 22.1.x: Upgrade to 22.1R3-S1 or later
Caveat Review Juniper release notes for any known compatibility issues or configuration changes between your current version and the target fixed version before upgrading

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

Fix this in Junos Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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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-2024-21594 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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