Skip to content
OpenAdvisories
High · 7.5 CVE-2026-21918 EUVD-2026-2697GHSA-9m47-29xf-m969

Junos OS: SRX and MX Series: When TCP packets occur in a specific sequence flowd crashes

Published Jan 15, 2026 · Updated Jan 15, 2026 · Assigned by juniper

Description

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.

Affected products

VendorProductAffectedFixed
Juniper Networks Junos OS < 22.4R3-S7, 23.2 – < 23.2R2-S3, 23.4 – < 23.4R2-S4, 24.2 – < 24.2R2 22.4R3-S7

Advisories 2

References