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    Dashboard / CVE / CVE-2026-33800

    CVE-2026-33800

    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, and LC2101/2103 and LC480. 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.

    Published:Jul 9, 2026
    Last Modified:Aug 26, 2026
    EPS:Jul 9, 2026
    EPSS Score:0.00269
    CVSS Score:6.5

    Affected Products

    Vendor
    Juniper
    Product
    Junos
    Vendor
    Juniper
    Product
    Lc2101
    Vendor
    Juniper
    Product
    Lc2103
    Vendor
    Juniper
    Product
    Lc4800
    Vendor
    Juniper
    Product
    Mpc1
    Vendor
    Juniper
    Product
    Mpc1 Q
    Vendor
    Juniper
    Product
    Mpc1e
    Vendor
    Juniper
    Product
    Mpc1e Q
    Vendor
    Juniper
    Product
    Mpc2
    Vendor
    Juniper
    Product
    Mpc2 Eq
    Vendor
    Juniper
    Product
    Mpc2 Q
    Vendor
    Juniper
    Product
    Mpc2e
    Vendor
    Juniper
    Product
    Mpc2e Eq
    Vendor
    Juniper
    Product
    Mpc2e Ng
    Vendor
    Juniper
    Product
    Mpc2e Ng Q
    Vendor
    Juniper
    Product
    Mpc2e P
    Vendor
    Juniper
    Product
    Mpc2e Q
    Vendor
    Juniper
    Product
    Mpc3e
    Vendor
    Juniper
    Product
    Mpc3e-3d-ng
    Vendor
    Juniper
    Product
    Mpc3e-3d-ng-q
    Vendor
    Juniper
    Product
    Mpc6e
    Vendor
    Juniper
    Product
    Mpc7e-10g
    Vendor
    Juniper
    Product
    Mpc7e-mrate
    Vendor
    Juniper
    Product
    Mpc8e
    Vendor
    Juniper
    Product
    Mpc9e
    Vendor
    Juniper Networks
    Product
    Junos Os

    Exploits

    No exploit reference

    Common Attack Pattern Enumeration and Classification (CAPEC)

    No CAPEC recorded yet

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    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High