CVE-2026-21918

HIGH

7.5

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.

CVE Details

CVSS v3.1 Score7.5

SeverityHIGH

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published1/15/2026

Last Modified1/23/2026

Sourcenvd

Honeypot Sightings0

Affected Products

juniper:junosjuniper:mx10004juniper:mx10008juniper:mx2008juniper:mx2010juniper:mx2020juniper:mx204juniper:mx240juniper:mx304juniper:mx480juniper:mx960juniper:srx1500juniper:srx1600juniper:srx2300juniper:srx300juniper:srx320juniper:srx340juniper:srx345juniper:srx380juniper:srx4100juniper:srx4120juniper:srx4200juniper:srx4300juniper:srx4600juniper:srx4700juniper:srx5400juniper:srx5600juniper:srx5800

Weaknesses (CWE)

CWE-415

References

https://kb.juniper.net/JSA106018(sirt@juniper.net)

https://supportportal.juniper.net/JSA106018(sirt@juniper.net)

IOC Correlations

No correlations recorded

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