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CVE-2026-33800

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

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
Juniper Networks / Junos OSaffected 0 before 23.2R2-S7; affected 23.4 before 23.4R2-S8; affected 24.2 before 24.2R2-S4; affected 24.4 before 24.4R2-S3; affected 25.2 before 25.2R2

CWE

CWE-606

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.