7.1

CVE-2026-33800

Junos OS: MX Series: In a VC scenario a high rate of micro-BFD session flaps will cause an FPC crash

An Unchecked Input for Loop Condition vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on MX Series allows an unauthenticated, adjacent attacker to cause a Denial-of-Service (DoS).Micro-BFD session flaps generate respective up/down events which are queued by PFEMAN for processing. Especially in a Virtual-Chassis (VC) scenario with locality‑bias configured, processing takes a significant amount of time for each event. If these sessions keep flapping, new events are constantly added, and in turn PFEMAN never completes processing these events. This results in the PFEMAN watchdog timer expiring, which causes the FPC to crash and restart, representing a complete service outage.


This issue only affects MX series FPCs up to and including MPC9. It does not affect MPC10/11, LC4800/9600 and MX304.

This issue affects Junos OS on MX Series:


  *  all versions before 23.2R2-S7,
  *  23.4 versions before 23.4R2-S8,
  *  24.2 versions before 24.2R2-S4,
  *  24.4 versions before 24.4R2-S3,
  *  25.2 versions before 25.2R2.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
HerstellerJuniper Networks
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Produkt Junos OS
Default Statusunaffected
Version 0
Version < 23.2R2-S7
Status affected
Version 23.4
Version < 23.4R2-S8
Status affected
Version 24.2
Version < 24.2R2-S4
Status affected
Version 24.4
Version < 24.4R2-S3
Status affected
Version 25.2
Version < 25.2R2
Status affected
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
sirt@juniper.net 6.5 2.8 3.6
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
sirt@juniper.net 7.1 0 0
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:X/RE:M/U:X
CWE-606 Unchecked Input for Loop Condition

The product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping.

https://supportportal.juniper.net/JSA110075