CVE-2026-21918
HIGHCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
2Description
A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX and MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). On all SRX and MX Series platforms, when during TCP session establishment a specific sequence of packets is encountered a double free happens. This causes flowd to crash and the respective FPC to restart. This issue affects Junos OS on SRX and MX Series: * all versions before 22.4R3-S7, * 23.2 versions before 23.2R2-S3, * 23.4 versions before 23.4R2-S4, * 24.2 versions before 24.2R2.
Analysis
Juniper Networks Junos OS on SRX and MX Series is vulnerable to a double free condition in the flow processing daemon that an unauthenticated network attacker can trigger via a specific TCP packet sequence, causing the daemon to crash and the Fabric Routing Card to restart. This denial-of-service vulnerability affects all versions before 22.4R3-S7, 23.2 before 23.2R2-S3, 23.4 before 23.4R2-S4, and 24.2 before 24.2R2, with no patch currently available. …
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Remediation
Within 7 days: Identify all affected systems and apply vendor patches promptly. Monitor vendor channels for patch availability.
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