CVE-2026-21905

HIGH EPSS 28.6%
Published Jan 15, 20265mo ago · Modified Jun 17, 20262w ago
8.7 CVSS 4.0
High
Find Similar
Published Jan 15, 2026 5mo ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
8.7
Exploitability
Impact
Vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:C/RE:M/U:Amber
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
28.6% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-835

Affected Products 113

VendorProductVersionRange
juniperjunos* <21.2
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.2any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos21.4any
juniperjunos22.4any
juniperjunos22.4any
juniperjunos22.4any
juniperjunos22.4any
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juniperjunos22.4any
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juniperjunos22.4any
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juniperjunos22.4any
juniperjunos22.4any
juniperjunos22.4any
juniperjunos22.4any
juniperjunos22.4any
juniperjunos22.4any
juniperjunos23.2any
juniperjunos23.2any
juniperjunos23.2any
juniperjunos23.2any
juniperjunos23.2any
juniperjunos23.2any
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juniperjunos23.2any
juniperjunos23.4any
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juniperjunos23.4any
juniperjunos23.4any
juniperjunos23.4any
juniperjunos23.4any
juniperjunos23.4any
juniperjunos23.4any
juniperjunos23.4any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.4any
juniperjunos24.4any
juniperjunos24.4any
juniperjunos24.4any
juniperjunos24.4any
juniperjunos25.2any
juniperjunos25.2any
juniperjunos25.2any
junipermx10004*any
junipermx10008*any
junipermx2008*any
junipermx2010*any
junipermx2020*any
junipermx204*any
junipermx240*any
junipermx304*any
junipermx480*any
junipermx960*any
junipersrx1500*any
junipersrx1600*any
junipersrx2300*any
junipersrx300*any
junipersrx320*any
junipersrx340*any
junipersrx345*any
junipersrx380*any
junipersrx4100*any
junipersrx4120*any
junipersrx4200*any
junipersrx4300*any
junipersrx4600*any
junipersrx4700*any
junipersrx5400*any
junipersrx5600*any
junipersrx5800*any

References 2

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.