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JunosOperating system · Juniper

CVE-2025-52946

HIGH · 7.5 CVSS v3.1 Published 2025-07-11
Fix available
A fix is available. Upgrade to 21.2 / 22.4 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 Use After Free vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Juniper Networks Junos OS Evolved allows an attacker sending a BGP update with a specifically malformed AS PATH to cause rpd to crash, resulting in a Denial of Service (DoS). Continuous receipt of the malformed AS PATH attribute will cause a sustained DoS condition. On all Junos OS and Junos OS Evolved platforms, the rpd process will crash and restart when a specifically malformed AS PATH is received within a BGP update and traceoptions are enabled. This issue only affects systems with BGP traceoptions enabled and requires a BGP session to be already established. Systems without BGP traceoptions enabled are not impacted by this issue. This issue affects:  Junos OS: * All versions before 21.2R3-S9,  * all versions of 21.4, * from 22.2 before 22.2R3-S6,  * from 22.4 before 22.4R3-S5,  * from 23.2 before 23.2R2-S3,  * from 23.4 before 23.4R2-S4,  * from 24.2 before 24.2R2;  Junos OS Evolved:  * All versions before 22.4R3-S5-EVO,  * from 23.2-EVO before 23.2R2-S3-EVO,  * from 23.4-EVO before 23.4R2-S4-EVO,  * from 24.2-EVO before 24.2R2-EVO. This is a more complete fix for previously published CVE-2024-39549 (JSA83011).

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 Use After Free vulnerability in Juniper's routing protocol daemon (rpd) allows an attacker with an established BGP session to send a specifically malformed AS PATH attribute, triggering a crash and DoS condition. The flaw only manifests when BGP traceoptions are enabled, making it a conditionally exploitable memory safety issue in BGP path attribute processing.

MitigationApply Juniper's vendor patches for the affected Junos OS/Evolved versions. Alternatively, if immediate patching is not feasible, disabling BGP traceoptions (if not required) eliminates the attack vector as a workaround.

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
Junos Os EvolvedOperating system
Affected:< 22.4= 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 Junos version
    Execute 'show version' or 'show version detail' on the device CLI to obtain the installed Junos OS or Junos OS Evolved version.
    Affected if The displayed version matches one of the affected ranges: Junos < 21.2, = 21.2, = 21.4, = 22.2, = 22.4, = 23.2, = 23.4, = 24.2 for Junos; or Junos OS Evolved < 22.4, = 22.4, = 23.2, = 23.4, = 24.2.
  2. Verify BGP is configured
    Execute 'show configuration protocols bgp' or review the BGP configuration to confirm BGP is enabled on the device.
    Affected if BGP is actively configured on the device.
  3. Check if BGP traceoptions are enabled
    Execute 'show configuration protocols bgp' and look for 'traceoptions' under the BGP hierarchy. Alternatively, run 'show bgp summary' and inspect whether traceoptions are active in the BGP configuration.
    Affected if BGP traceoptions are explicitly configured and enabled - this is the required condition for the vulnerability to be exploitable.
  4. Confirm BGP sessions are established
    Execute 'show bgp summary' or 'show bgp neighbor' to list active BGP peers and session states.
    Affected if One or more established BGP sessions exist, creating the attack surface for a remote peer to send malformed AS PATH attributes.

You are affected if the device runs a vulnerable Junos version, has BGP configured with traceoptions enabled, and maintains active BGP peer sessions that could receive the malformed AS PATH attribute.

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 / 22.4 or later
Fixed in 21.222.4
Interim mitigation

Apply Juniper's vendor patches for the affected Junos OS/Evolved versions. Alternatively, if immediate patching is not feasible, disabling BGP traceoptions (if not required) eliminates the attack vector as a workaround.

Recommended fix High confidence

Junos OS: 21.2R3-S9, 22.2R3-S6, 22.4R3-S5, 23.2R2-S3, 23.4R2-S4, or 24.2R2 | Junos OS Evolved: 22.4R3-S5-EVO, 23.2R2-S3-EVO, 23.4R2-S4-EVO, or 24.2R2-EVO

  1. 1. Identify the current Junos OS or Junos OS Evolved version running on the device using 'show version'
  2. 2. Based on your current version, identify the minimum fixed release needed from: Junos OS: 21.2R3-S9, 22.2R3-S6, 22.4R3-S5, 23.2R2-S3, 23.4R2-S4, or 24.2R2 | Junos OS Evolved: 22.4R3-S5-EVO, 23.2R2-S3-EVO, 23.4R2-S4-EVO, or 24.2R2-EVO
  3. 3. Download the appropriate fixed Junos upgrade image from the Juniper Networks support portal
  4. 4. Upload the upgrade image to the device using 'request system software add <path-to-package>'
  5. 5. Reboot the device using 'request system reboot' to apply the new software version
  6. 6. After reboot, verify the rpd process is running and BGP sessions are established using 'show bgp summary'
  7. 7. Alternatively as a mitigation: disable BGP traceoptions if not required using 'delete protocols bgp traceoptions' under the respective hierarchy
Caveat Standard Junos upgrade precautions apply - test in lab environment first, ensure configuration backup exists, and plan for potential brief service interruption during reboot

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
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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

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Peer-ranked notes from engineers who’ve handled CVE-2025-52946 in production — separate from our analysis above.

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What this is

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