CVE-2025-52952

Adjacent FPC restart via malformed CFM packet

Published Jul 11, 2025 · Updated Jul 11, 2025

Out-of-bounds write in Junos OS CFM daemons before 22.2R3-S1 and 22.4 before 22.4R2 allows attackers to restart FPCs. The pfe ukern, cfmman, and cfmd modules write beyond a buffer boundary while processing a malformed CFM packet. Exposure requires adjacent network access and nondefault enhanced CFM mode on an affected MX Series MPC; repeated packets sustain service interruption through FPC crashes and restarts.

CVSS severity7.1
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in Junos OS CFM daemons before 22.2R3-S1 and 22.4 before 22.4R2 allows attackers to restart FPCs. The pfe ukern, cfmman, and cfmd modules write beyond a buffer boundary while processing a malformed CFM packet. Exposure requires adjacent network access and nondefault enhanced CFM mode on an affected MX Series MPC; repeated packets sustain service interruption through FPC crashes and restarts.

The record

CVE
CVE-2025-52952
Published
Jul 11, 2025
Updated
Jul 11, 2025
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-787, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 11, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <22.2R3-S1
  2. Affected versionversion=22.4 <22.4R2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=0 <22.2R3-S1; version=22.4 <22.4R2

Published CVSS scores

7.1Juniper NetworksCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:C/RE:M/U:Green
6.5Juniper NetworksCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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