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JunosOperating system · Juniper

CVE-2025-30645

HIGH · 7.5 CVSS v3.1 Published 2025-04-09
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
A NULL Pointer Dereference vulnerability in the flow daemon (flowd) of Juniper Networks Junos OS on SRX Series allows an attacker causing specific, valid control traffic to be sent out of a Dual-Stack (DS) Lite tunnel to crash the flowd process, resulting in a Denial of Service (DoS).  Continuous triggering of specific control traffic will create a sustained Denial of Service (DoS) condition. On all SRX platforms, when specific, valid control traffic needs to be sent out of a DS-Lite tunnel, a segmentation fault occurs within the flowd process, resulting in a network outage until the flowd process restarts. This issue affects Junos OS on SRX Series: * All versions before 21.2R3-S9, * from 21.4 before 21.4R3-S9, * from 22.2 before 22.2R3-S5, * from 22.4 before 22.4R3-S6, * from 23.2 before 23.2R2-S3, * from 23.4 before 23.4R2.

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 confidence

A NULL pointer dereference vulnerability in the flow daemon (flowd) of Juniper Junos OS on SRX Series devices causes a segmentation fault when specific valid control traffic is transmitted through a Dual-Stack Lite tunnel, crashing the flowd process and creating a denial of service condition.

MitigationApply the vendor-supplied Junos OS patches: upgrade to 21.2R3-S9, 21.4R3-S9, 22.2R3-S5, 22.4R3-S6, 23.2R2-S3, 23.4R2 or later versions. Until patched, monitor for flowd crashes and consider isolating affected devices from untrusted traffic.

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

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 version' to confirm the device is an SRX Series appliance
    Affected if Device is not SRX Series (vulnerability only affects SRX hardware)
  2. Check Junos OS version
    Run 'show version' and compare the installed Junos version against the affected list: < 21.2, 21.2, 21.4, 22.2, 22.4, 23.2, or 23.4
    Affected if The installed version matches any of the affected versions listed
  3. Verify Dual-Stack Lite configuration
    Run 'show configuration | match ds-lite' or 'show configuration tunnel' to check if DS-Lite tunnels are configured
    Affected if Dual-Stack Lite tunnel interfaces are configured on the device
  4. Inspect for flowd crash logs
    Run 'show log messages | match flowd' or check '/var/log/messages' for recent flowd crash entries
    Affected if Recent flowd process crashes or segmentation faults are logged

Device is affected if it is an SRX Series running any of the listed affected Junos versions AND has Dual-Stack Lite tunnels configured, or if flowd crashes have already occurred.

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 vendor-supplied Junos OS patches: upgrade to 21.2R3-S9, 21.4R3-S9, 22.2R3-S5, 22.4R3-S6, 23.2R2-S3, 23.4R2 or later versions. Until patched, monitor for flowd crashes and consider isolating affected devices from untrusted traffic.

Recommended fix High confidence

21.2R3-S9 (or later), 21.4R3-S9 (or later), 22.2R3-S5 (or later), 22.4R3-S6 (or later), 23.2R2-S3 (or later), or 23.4R2

  1. 1. Identify the current Junos OS version running on the SRX Series device using 'show version' command.
  2. 2. Determine which version branch (21.2, 21.4, 22.2, 22.4, 23.2, or 23.4) your current version belongs to.
  3. 3. Download the appropriate fixed version for your branch from the Juniper Networks support portal: 21.2R3-S9 or later, 21.4R3-S9 or later, 22.2R3-S5 or later, 22.4R3-S6 or later, 23.2R2-S3 or later, or 23.4R2 or later.
  4. 4. Upload the Junos OS upgrade package to the SRX device using 'file copy' or FTP/SCP to the /var/tmp directory.
  5. 5. Initiate the software installation using 'request system software add /var/tmp/<package-name>' command.
  6. 6. After installation completes, reboot the device using 'request system reboot' command to load the new Junos OS version.
  7. 7. Verify the upgrade was successful by running 'show version' and confirming the new version is installed.
  8. 8. Verify flowd process is running normally using 'show system processes extensive | match flowd'.
Caveat Standard Junos OS upgrade considerations apply - review release notes for any configuration changes, ensure valid Junos OS contract/subscription is in place, and plan maintenance window as upgrade will cause brief outage

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

Fix this in Junos Scoped from the published advisory
  • Consultation6.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,730
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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-2025-30645 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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