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CVE-2026-21905— Junos OS: SRX Series, MX Series with MX-SPC3 or MS-MPC: Receipt of multiple specific SIP messages results in flow management process crash

CVSS 7.5 · High EPSS 0.02% · P5
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I. Basic Information for CVE-2026-21905

Vulnerability Information
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Vulnerability Title
Junos OS: SRX Series, MX Series with MX-SPC3 or MS-MPC: Receipt of multiple specific SIP messages results in flow management process crash
Source: NVD (National Vulnerability Database)
Vulnerability Description
A Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in the SIP application layer gateway (ALG) of Juniper Networks Junos OS on SRX Series and MX Series with MX-SPC3 or MS-MPC allows an unauthenticated network-based attacker sending specific SIP messages over TCP to crash the flow management process, leading to a Denial of Service (DoS). On SRX Series, and MX Series with MX-SPC3 or MS-MPC service cards, receipt of multiple SIP messages causes the SIP headers to be parsed incorrectly, eventually causing a continuous loop and leading to a watchdog timer expiration, crashing the flowd process on SRX Series and MX Series with MX-SPC3, or mspmand process on MX Series with MS-MPC. This issue only occurs over TCP. SIP messages sent over UDP cannot trigger this issue. This issue affects Junos OS on SRX Series and MX Series with MX-SPC3 and MS-MPC: * all versions before 21.2R3-S10,  * from 21.4 before 21.4R3-S12,  * from 22.4 before 22.4R3-S8,  * from 23.2 before 23.2R2-S5,  * from 23.4 before 23.4R2-S6,  * from 24.2 before 24.2R2-S3,  * from 24.4 before 24.4R2-S1,  * from 25.2 before 25.2R1-S1, 25.2R2.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
不可达退出条件的循环(无限循环)
Source: NVD (National Vulnerability Database)
Vulnerability Title
Juniper Networks Junos OS 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Juniper Networks Junos OS是美国瞻博网络（Juniper Networks）公司的一套专用于该公司的硬件设备的网络操作系统。该操作系统提供了安全编程接口和Junos SDK。 Juniper Networks Junos OS 21.2R3-S10之前版本、21.4R3-S12之前版本、22.4R3-S8之前版本、23.2R2-S5之前版本、23.4R2-S6之前版本、24.2R2-S3之前版本、24.4R2-S1之前版本、25.2R1-S1和25.2R2之前版本存在安全漏洞，该漏
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

VendorProductAffected VersionsCPESubscribe
Juniper NetworksJunos OS 0 ~ 21.2R3-S10 -

II. Public POCs for CVE-2026-21905

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III. Intelligence Information for CVE-2026-21905

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Same Patch Batch · Juniper Networks · 2026-01-15 · 23 CVEs total

CVE-2026-219207.5 HIGHJunos OS: SRX Series: If a specific request is processed by the DNS subsystem flowd will c
CVE-2026-219187.5 HIGHJunos OS: SRX and MX Series: When TCP packets occur in a specific sequence flowd crashes
CVE-2025-600037.5 HIGHJunos OS and Junos OS Evolved: BGP update with a set of specific attributes causes rpd cra
CVE-2026-219177.5 HIGHJunos OS: SRX Series: Specifically malformed SSL packet causes FPC crash
CVE-2026-219147.5 HIGHJunos OS: SRX Series: A specifically malformed GTP message will cause an FPC crash
CVE-2026-219137.5 HIGHJunos OS: EX4000: A high volume of traffic destined to the device leads to a crash and res
CVE-2026-219067.5 HIGHJunos OS: SRX Series: With GRE performance acceleration enabled, receipt of a specific ICM
CVE-2025-599607.4 HIGHJunos OS and Junos OS Evolved: DHCP Option 82 messages from clients being passed unmodifie
CVE-2026-219087.1 HIGHJunos OS and Junos OS Evolved: Use after free vulnerability In 802.1X authentication daemo
CVE-2026-219216.5 MEDIUMJunos OS and Junos OS Evolved: When telemetry collectors are frequently subscribing and un
CVE-2026-219116.5 MEDIUMJunos OS Evolved: Flapping management interface causes MAC learning on label-switched inte
CVE-2026-219106.5 MEDIUMJunos OS: EX4k Series, QFX5k Series: In an EVPN-VXLAN configuration link flaps cause Inter
CVE-2026-219096.5 MEDIUMJunos OS and Junos OS Evolved: Receipt of specific IS-IS update packet causes memory leak
CVE-2026-219036.5 MEDIUMJunos OS: Subscribing to telemetry sensors at scale causes all FPCs to crash
CVE-2026-02036.5 MEDIUMJunos OS: Receipt of a specifically malformed ICMP packet causes an FPC restart
CVE-2025-529876.1 MEDIUMParagon Automation: A clickjacking vulnerability in the web server configuration has been
CVE-2026-219075.9 MEDIUMJunos Space: TLS/SSL server supports use of static key ciphers (ssl-static-key-ciphers)
CVE-2025-600115.8 MEDIUMJunos OS and Junos OS Evolved: Optional transitive BGP attribute is modified before propag
CVE-2026-219125.5 MEDIUMJunos OS: MX10k Series: 'show system firmware' CLI command may lead to LC480 or LC2101 lin
CVE-2025-600075.5 MEDIUMJunos OS: A specifically crafted 'show chassis' command causes chassisd to crash

Showing top 20 of 23 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Junos OS
Same vendor: Juniper Networks
Same weakness: CWE-835

V. Comments for CVE-2026-21905

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