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JunosOperating system · Juniper

CVE-2025-30651

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 Buffer Access with Incorrect Length Value vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network-based attacker to cause a Denial of Service (DoS). When an attacker sends a specific ICMPv6 packet to an interface with "protocols router-advertisement" configured, rpd crashes and restarts. Continued receipt of this packet will cause a sustained DoS condition.  This issue only affects systems configured with IPv6. This issue affects Junos OS:  * All versions before 21.2R3-S9,  * from 21.4 before 21.4R3-S10, * from 22.2 before 22.2R3-S6, * from 22.4 before 22.4R3-S4, * from 23.2 before 23.2R2-S2, * from 23.4 before 23.4R2; and Junos OS Evolved: * All versions before 21.2R3-S9-EVO, * from 21.4-EVO before 21.4R3-S10-EVO, * from 22.2-EVO before 22.2R3-S6-EVO, * from 22.4-EVO before 22.4R3-S4-EVO, * from 23.2-EVO before 23.2R2-S2-EVO, * from 23.4-EVO before 23.4R2-EVO.

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 buffer access with incorrect length value vulnerability exists in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved. When an attacker sends a specifically crafted ICMPv6 packet to an interface configured with 'protocols router-advertisement', it causes rpd to crash and restart, creating a sustained denial of service condition.

MitigationApply the appropriate Junos OS or Junos OS Evolved software update per the version-specific guidance. As a workaround, disable IPv6 router-advertisement on exposed interfaces if IPv6 is not required.

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
Junos Os EvolvedOperating 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 Junos OS variant and version
    Run 'show version' or 'show version detail' to determine if the device runs Junos OS or Junos OS Evolved, and note the exact version number
    Affected if The version matches < 21.2, = 21.2, = 21.4, = 22.2, = 22.4, = 23.2, or = 23.4
  2. Confirm router-advertisement protocol is configured
    Run 'show configuration protocols router-advertisement' to check if IPv6 router-advertisement is enabled on any interface
    Affected if The command returns configuration output showing router-advertisement is active on one or more interfaces
  3. Verify IPv6 is enabled on exposed interfaces
    Run 'show configuration interfaces | display set | match inet6' or 'show ipv6 interface' to see which interfaces have IPv6 configured
    Affected if Interfaces with IPv6 are present AND router-advertisement is configured on those interfaces

The device is affected if it runs a version in the list AND has IPv6 router-advertisement protocol enabled on any interface, allowing a remote attacker to send malicious ICMPv6 packets causing rpd restarts.

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 or Junos OS Evolved software update per the version-specific guidance. As a workaround, disable IPv6 router-advertisement on exposed interfaces if IPv6 is not required.

Recommended fix High confidence

Upgrade to one of the fixed versions: Junos OS 21.2R3-S9, 21.4R3-S10, 22.2R3-S6, 22.4R3-S4, 23.2R2-S2, or 23.4R2 (or corresponding Junos OS Evolved versions with -EVO suffix)

  1. 1. Identify the current Junos OS or Junos OS Evolved version by running 'show version' in the CLI.
  2. 2. Determine the appropriate fixed version based on the current version branch: For 21.2.x upgrade to 21.2R3-S9, for 21.4.x upgrade to 21.4R3-S10, for 22.2.x upgrade to 22.2R3-S6, for 22.4.x upgrade to 22.4R3-S4, for 23.2.x upgrade to 23.2R2-S2, for 23.4.x upgrade to 23.4R2.
  3. 3. Schedule a maintenance window as the upgrade will require a system reboot.
  4. 4. Before upgrading, ensure you have a valid backup of the configuration using 'request system snapshot' or by exporting the configuration.
  5. 5. Download the appropriate Junos OS or Junos OS Evolved upgrade package from the Juniper Networks support portal.
  6. 6. Upload the upgrade package to the device using 'request system software add' command.
  7. 7. Reboot the device using 'request system reboot' to complete the upgrade.
  8. 8. After the device restarts, verify the new version is running with 'show version' and confirm the rpd process is stable with 'show routing-engine'.
Caveat Standard Junos upgrade considerations apply - ensure compatibility with existing scripts/features and plan for downtime. Review Junos upgrade guide for your version branch.

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
  • Testing8.0 h
  • Review / QA3.0 h
20.0 hours of engineering $3,420
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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-2025-30651 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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