CVE-2026-21918 — Junos OS: SRX and MX Series: When TCP packets occur in a specific sequence flowd crashes

Description (CNA)

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 (CNA)

Vendor / product	Versions
Juniper Networks / Junos OS	affected 0 before 22.4R3-S7; affected 23.2 before 23.2R2-S3; affected 23.4 before 23.4R2-S4; affected 24.2 before 24.2R2

CWE

CWE-415

References

https://supportportal.juniper.net/JSA106018
https://kb.juniper.net/JSA106018

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.