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JunosOperating system · Juniper

CVE-2025-52949

MEDIUM · 6.5 CVSS v3.1 Published 2025-07-11
Fix available
A fix is available. Upgrade to 21.4 / 22.2 or later.
See remediation →
70/100
Remediation priority · Elevated
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 Handling of Length Parameter Inconsistency vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows a logically adjacent BGP peer sending a specifically malformed BGP packet to cause rpd to 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. Only systems configured for Ethernet Virtual Private Networking (EVPN) signaling are vulnerable to this issue.  This issue affects iBGP and eBGP, and both IPv4 and IPv6 are affected by this vulnerability.This issue affects: Junos OS:  * all versions before 21.4R3-S11,  * from 22.2 before 22.2R3-S7,  * from 22.4 before 22.4R3-S7,  * from 23.2 before 23.2R2-S4,  * from 23.4 before 23.4R2-S5,  * from 24.2 before 24.2R2-S1,  * from 24.4 before 24.4R1-S3, 24.4R2;  Junos OS Evolved:  * all versions before 22.2R3-S7-EVO,  * from 22.4-EVO before 22.4R3-S7-EVO,  * from 23.2-EVO before 23.2R2-S4-EVO,  * from 23.4-EVO before 23.4R2-S5-EVO,  * from 24.2-EVO before 24.2R2-S1-EVO,  * from 24.4-EVO before 24.4R1-S3-EVO, 24.4R2-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 length parameter inconsistency in BGP packet handling in Juniper rpd daemon allows a logically adjacent BGP peer to send a malformed BGP packet (specifically in EVPN signaling context) that causes rpd to crash and restart, creating a sustained DoS condition. The vulnerability affects both iBGP and eBGP across IPv4 and IPv6.

MitigationUpgrade Junos OS/Evolved to the specified fixed versions (21.4R3-S11, 22.2R3-S7, 22.4R3-S7, 23.2R2-S4, 23.4R2-S5, 24.2R2-S1, 24.4R1-S3 or later). Only EVPN-configured systems are vulnerable.

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= 24.4
Junos Os EvolvedOperating system
Affected:< 22.2= 22.2= 22.4= 23.2= 23.4= 24.2= 24.4

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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/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 the Junos version
    Run `show version` or `show version detail` to obtain the exact Junos version installed on the device
    Affected if The version matches one of the affected versions: < 21.4, = 21.4, = 22.2, = 22.4, = 23.2, = 23.4, = 24.2, = 24.4 (for Junos) or < 22.2, = 22.2, = 22.4, = 23.2, = 23.4, = 24.2, = 24.4 (for Junos Evolved)
  2. Confirm Junos platform type
    Run `show version` to determine if the device runs Junos or Junos OS Evolved
    Affected if The device runs either Junos or Junos OS Evolved and the version matches the affected ranges listed for that platform
  3. Verify if EVPN is configured
    Run `show configuration protocols evpn` or `show evpn database` to check for EVPN configuration and operational state
    Affected if EVPN is configured or operational on the device - this is a required condition for the vulnerability to be exploitable
  4. Check BGP neighbor status
    Run `show bgp summary` or `show configuration protocols bgp` to see if BGP peers are configured and established
    Affected if BGP is configured and active, particularly with adjacent peers capable of sending BGP packets
  5. Inspect rpd daemon status
    Run `show routing daemon` or `show system processes routing` to verify the rpd daemon is running
    Affected if The rpd (routing) daemon is active, as this is the component that crashes when processing the malformed BGP packet

A system is affected if it runs a vulnerable Junos or Junos OS Evolved version AND has EVPN configured, with BGP active and the rpd daemon running - the vulnerability requires all these conditions to be present for exploitation.

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 / 22.2 or later
Fixed in 21.422.2
Interim mitigation

Upgrade Junos OS/Evolved to the specified fixed versions (21.4R3-S11, 22.2R3-S7, 22.4R3-S7, 23.2R2-S4, 23.4R2-S5, 24.2R2-S1, 24.4R1-S3 or later). Only EVPN-configured systems are vulnerable.

Recommended fix High confidence

Upgrade to Junos OS 21.4R3-S11/22.2R3-S7/22.4R3-S7/23.2R2-S4/23.4R2-S5/24.2R2-S1/24.4R1-S3/24.4R2 or Junos OS Evolved 22.2R3-S7-EVO/22.4R3-S7-EVO/23.2R2-S4-EVO/23.4R2-S5-EVO/24.2R2-S1-EVO/24.4R1-S3-EVO/24.4R2-EVO depending on your release train

  1. Identify the current Junos OS or Junos OS Evolved version running on the device
  2. For Junos OS: Upgrade to one of the following fixed versions: 21.4R3-S11, 22.2R3-S7, 22.4R3-S7, 23.2R2-S4, 23.4R2-S5, 24.2R2-S1, 24.4R1-S3, or 24.4R2
  3. For Junos OS Evolved: Upgrade to one of the following fixed versions: 22.2R3-S7-EVO, 22.4R3-S7-EVO, 23.2R2-S4-EVO, 23.4R2-S5-EVO, 24.2R2-S1-EVO, 24.4R1-S3-EVO, or 24.4R2-EVO
  4. After upgrade, verify that the routing protocol daemon (rpd) is running stable
  5. Ensure the device is configured with EVPN signaling as this is the prerequisite condition for exploitation
Caveat Review Juniper Networks release notes for any compatibility or configuration changes between your current version and the target fixed version before upgrading

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

Fix this in Junos Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,770
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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-2025-52949 in production — separate from our analysis above.

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