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JunosOperating system · Juniper

CVE-2025-30644

HIGH · 7.5 CVSS v3.1 Published 2025-04-09
Fix available
A fix is available. Upgrade to 21.4 or later.
See remediation →
80/100
Remediation priority · High
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 Heap-based Buffer Overflow vulnerability in the flexible PIC concentrator (FPC) of Juniper Networks Junos OS on EX2300, EX3400, EX4100, EX4300, EX4300MP, EX4400, EX4600, EX4650-48Y, and QFX5k Series allows an attacker to send a specific DHCP packet to the device, leading to an FPC crash and restart, resulting in a Denial of Service (DoS). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. Under a rare timing scenario outside the attacker's control, memory corruption may be observed when DHCP Option 82 is enabled, leading to an FPC crash and affecting packet forwarding. Due to the nature of the heap-based overflow, exploitation of this vulnerability could also lead to remote code execution within the FPC, resulting in complete control of the vulnerable component. This issue affects Junos OS on EX2300, EX3400, EX4100, EX4300, EX4300MP, EX4400, EX4600, EX4650-48Y, and QFX5k Series: * All versions before 21.4R3-S9,  * from 22.2 before 22.2R3-S5,  * from 22.4 before 22.4R3-S5,  * from 23.2 before 23.2R2-S3,  * from 23.4 before 23.4R2-S3,  * from 24.2 before 24.2R2.

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

Heap-based buffer overflow in Juniper Junos OS flexible PIC concentrator (FPC) allows remote attackers to send a crafted DHCP packet causing FPC crash/restart (DoS). With DHCP Option 82 enabled under rare timing, memory corruption may occur, and exploitation could lead to remote code execution within the FPC.

MitigationApply Juniper-supplied patches: upgrade to 21.4R3-S9, 22.2R3-S5, 22.4R3-S5, 23.2R2-S3, 23.4R2-S3, or 24.2R2 or later per the version-specific guidance.

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:< 21.4= 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
Adjacent
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/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 Junos OS version
    Run 'show version' or 'show version detail' to obtain the installed Junos version
    Affected if Version matches < 21.4, 21.4, 22.2, 22.4, 23.2, 23.4, or 24.2 (versions before the fixed releases)
  2. Confirm FPC hardware presence
    Run 'show chassis fpc' or 'show fpc' to verify flexible PIC concentrator hardware is present in the device
    Affected if FPC is present - the vulnerability exists only in the FPC component
  3. Check DHCP Option 82 configuration
    Run 'show configuration | match "option 82"' or examine DHCP relay/broker configuration for 'option-82' or 'relay-agent' settings
    Affected if DHCP Option 82 is enabled - this is the required configuration for the overflow to be exploitable

A device is affected if it runs a vulnerable Junos version, contains FPC hardware, and has DHCP Option 82 enabled in the DHCP relay configuration.

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 21.4 or later
Fixed in 21.4
Interim mitigation

Apply Juniper-supplied patches: upgrade to 21.4R3-S9, 22.2R3-S5, 22.4R3-S5, 23.2R2-S3, 23.4R2-S3, or 24.2R2 or later per the version-specific guidance.

Recommended fix High confidence

Upgrade to one of: 21.4R3-S9, 22.2R3-S5, 22.4R3-S5, 23.2R2-S3, 23.4R2-S3, or 24.2R2 (or later stable releases) depending on your current version branch

  1. 1. Identify the current Junos OS version running on the device using 'show version' command
  2. 2. Determine the appropriate upgrade path based on the current version and hardware model (EX2300, EX3400, EX4100, EX4300, EX4300MP, EX4400, EX4600, EX4650-48Y, or QFX5k Series)
  3. 3. Download the appropriate Junos OS upgrade package from the Juniper Networks support portal (supportportal.juniper.net)
  4. 4. Transfer the upgrade package to the device using SCP or USB storage
  5. 5. Verify the integrity of the upgrade package using the SHA-256 checksum provided by Juniper
  6. 6. Initiate the upgrade using 'request system software add <package-name>' command
  7. 7. Reboot the device after successful installation using 'request system reboot' command
  8. 8. Verify the new version is installed and all FPCs are online using 'show version' and 'show chassis fpc' commands
Caveat Review Juniper release notes for your target version for any configuration changes, deprecated features, or migration considerations before upgrading

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 / QA4.0 h
22.0 hours of engineering $3,860
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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-2025-30644 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
  • 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