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JunosOperating system · Juniper

CVE-2025-52981

HIGH · 7.5 CVSS v3.1 Published 2025-07-11
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 Improper Check for Unusual or Exceptional Conditions vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX1600, SRX2300, SRX 4000 Series, and SRX5000 Series with SPC3 allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). If a sequence of specific PIM packets is received, this will cause a flowd crash and restart. This issue affects Junos OS: * all versions before 21.2R3-S9, * 21.4 versions before 21.4R3-S11, * 22.2 versions before 22.2R3-S7, * 22.4 versions before 22.4R3-S6, * 23.2 versions before 23.2R2-S4, * 23.4 versions before 23.4R2-S4, * 24.2 versions before 24.2R2. This is a similar, but different vulnerability than the issue reported as CVE-2024-47503, published in JSA88133.

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

A denial-of-service vulnerability exists in the flow processing daemon (flowd) of Juniper Junos OS on SRX1600, SRX2300, SRX4000/5000 Series with SPC3. An unauthenticated network attacker can trigger a flowd crash and restart by sending a specific sequence of PIM (Protocol Independent Multicast) packets. The vulnerability stems from improper error handling where the code fails to check for unusual or exceptional conditions properly.

MitigationApply the appropriate Junos OS software update (21.2R3-S9, 21.4R3-S11, 22.2R3-S7, 22.4R3-S6, 23.2R2-S4, 23.4R2-S4, or 24.2R2 or later) to resolve this issue. As a temporary workaround, consider filtering untrusted PIM traffic at network borders.

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= 22.2= 22.4= 23.2= 23.4= 24.2

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 your SRX model and SPC3 status
    Run 'show chassis hardware' or 'show system information' to confirm the device is an SRX1600, SRX2300, SRX4000, or SRX5000 Series with SPC3 module installed
    Affected if Device is not one of these models or does not have SPC3 - the vulnerability does not apply
  2. Check installed Junos OS version
    Run 'show version' and locate the Junos OS version string (for example, 22.4R1)
    Affected if Version matches one of the affected releases: any version before 21.2, or exactly 21.2, 21.4, 22.2, 22.4, 23.2, 23.4, or 24.2
  3. Determine if PIM is enabled
    Run 'show protocols pim' or check the configuration with 'show configuration protocols pim'
    Affected if PIM is enabled and accepting traffic - only then can the malicious packet sequence be delivered
  4. Check flowd crash history
    Run 'show system core-dumps' or 'show log messages' for recent flowd crash events, especially around times of unexpected flowd restarts
    Affected if Flowd has recently crashed or restarted without an explicit admin action

You are affected if you run an affected Junos version (21.2, 21.4, 22.2, 22.4, 23.2, 23.4, or 24.2, or any version before 21.2) on an SPC3-equipped SRX1600/2300/4000/5000 with PIM protocol enabled, and your flowd has exhibited unexplained crashes.

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 software update (21.2R3-S9, 21.4R3-S11, 22.2R3-S7, 22.4R3-S6, 23.2R2-S4, 23.4R2-S4, or 24.2R2 or later) to resolve this issue. As a temporary workaround, consider filtering untrusted PIM traffic at network borders.

Recommended fix High confidence

Upgrade to 21.2R3-S9+ / 21.4R3-S11+ / 22.2R3-S7+ / 22.4R3-S6+ / 23.2R2-S4+ / 23.4R2-S4+ / 24.2R2+ (choose the appropriate branch based on current version)

  1. 1. Identify the current Junos OS version running on the affected SRX device (SRX1600, SRX2300, SRX4000 Series, or SRX5000 Series with SPC3)
  2. 2. Based on your current version branch, plan upgrade to the minimum fixed release: for 21.2.x upgrade to 21.2R3-S9 or later; for 21.4.x upgrade to 21.4R3-S11 or later; for 22.2.x upgrade to 22.2R3-S7 or later; for 22.4.x upgrade to 22.4R3-S6 or later; for 23.2.x upgrade to 23.2R2-S4 or later; for 23.4.x upgrade to 23.4R2-S4 or later; for 24.2.x upgrade to 24.2R2 or later
  3. 3. Before upgrading, back up the current configuration and review the Junos upgrade documentation for your specific hardware platform
  4. 4. Download the appropriate Junos OS upgrade package from the Juniper Networks support portal (supportportal.juniper.net)
  5. 5. Upgrade the device during a planned maintenance window since the flowd daemon will restart as part of the upgrade
  6. 6. After upgrade, verify the new Junos version is installed and the device is operating normally
  7. 7. Monitor the device for any unusual behavior and verify flowd process stability
Caveat Standard Junos upgrade risks apply - ensure configuration compatibility and plan for brief downtime during upgrade

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-2025-52981 in production — separate from our analysis above.

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