Junos
CVE-2026-21918
HIGH
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
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. An attacker on the network can exploit this vulnerability without authentication or user interaction to disrupt service availability.
Technical ContextAI
Affects Junos. 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,
RemediationAI
Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.
named in ISC BIND 9.x before 9.9.8-P4 and 9.10.x before 9.10.3-P4 does not properly handle DNAME records when parsing fe
named in ISC BIND 9.x before 9.9.8-P4 and 9.10.x before 9.10.3-P4 allows remote attackers to cause a denial of service (
A PHP External Variable Modification vulnerability in J-Web of Juniper Networks Junos OS on EX Series and SRX Series all
jsdm/ajax/port.php in J-Web in Juniper Junos before 10.4R13, 11.4 before 11.4R7, 12.1 before 12.1R5, 12.2 before 12.2R3,
Juniper Junos 11.4 before R11, 12.1 before R9, 12.1X44 before D30, 12.1X45 before D20, 12.1X46 before D15, 12.1X47 befor
NFX Series devices using Juniper Networks Junos OS are susceptible to a local command execution vulnerability thereby al
NFX Series devices using Juniper Networks Junos OS are susceptible to a local code execution vulnerability thereby allow
Insufficient validation of environment variables in the telnet client supplied in Junos OS can lead to stack-based buffe
An Out-of-Bounds Write vulnerability in the H.323 ALG of Juniper Networks Junos OS allows an unauthenticated, network-ba
On QFX10000 Series devices using Juniper Networks Junos OS when configured as transit IP/MPLS penultimate hop popping (P
A Missing Release of Memory after Effective Lifetime vulnerability in the kernel of Juniper Networks Junos OS allows an
An Uncontrolled Memory Allocation vulnerability leading to a Heap-based Buffer Overflow in the packet forwarding engine
Same weakness CWE-415 – Double Free
View allSame technique Denial Of Service
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External POC / Exploit Code
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