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Fencer Vulns
medium 6.5

CVE-2025-52952 json

Junos OS: MX Series with MPC-BUILTIN, MPC 1 through MPC 9: Receipt and processing of a malformed packet causes one or more FPCs to crash

published 2025-07-11 15 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-21157

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

An Out-of-bounds Write vulnerability in the connectivity fault management (CFM) daemon of Juniper Networks Junos OS on MX Series with MPC-BUILTIN, MPC1 through MPC9 line cards allows an unauthenticated adjacent attacker to send a malformed 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.

This issue affects Juniper Networks: Junos OS: * All versions before 22.2R3-S1, * from 22.4 before 22.4R2.

This feature is not enabled by default.

Patch / fix

  • Juniper Networks Junos OS 22.2R3-S1, 22.4R2

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
15 mo ago

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 7.1 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/V:C/RE:M/U:Green
CNA 4.0 7.1 CVSS: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

Affected products

  • Juniper Networks Junos OS

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.