CVE-2026-21903
MEDIUMCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
2Description
A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker, authenticated with low privileges to cause a Denial-of-Service (DoS). Subscribing to telemetry sensors at scale causes all FPC connections to drop, resulting in an FPC crash and restart. The issue was not seen when YANG packages for the specific sensors were installed. This issue affects Junos OS: * all versions before 22.4R3-S7, * 23.2 version before 23.2R2-S4, * 23.4 versions before 23.4R2.
Analysis
Denial-of-service in Juniper Junos OS Packet Forwarding Engine allows authenticated attackers to crash Forwarding Processor Cards by subscribing to telemetry sensors at scale, forcing service restarts and network disruption. The vulnerability affects Junos versions before 22.4R3-S7, 23.2R2-S4, and 23.4R2, with no patch currently available. …
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Remediation
Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.
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