01 Record

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

HighPUBLISHEDCNA: juniper

CNA base score8.7 CVSS v4.0CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/V:C/RE:M/U:Amber

View raw JSON

02 Description

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

03 Exploitation and scoring

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.40% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 34.7% of scored records. A rank, not a probability.

NVD base score

8.7 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Analyzed. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2026-01-15 20:19Z9 MO AGO

Last updated

2026-01-16 16:26Z9 MO AGO

Reserved

2026-01-05

Assigning CNA

juniper

Record state

PUBLISHED

Severity

High (CVSS 8.7)

CNA CVSS vector

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/AU:Y/R:A/V:C/RE:M/U:Amber

Weaknesses

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')Base

Data version

5.2

Document digest

4da00991f25a68d5aae3956b14d8460f207c5e588a5cf436c83e11b1d92cde2f

05 Affected products

VendorProductVersionsPlatforms

Juniper NetworksJunos OS0 to < 21.2R3-S10, 21.4 to < 21.4R3-S12, 22.4 to < 22.4R3-S8, 23.2 to < 23.2R2-S5, 23.4 to < 23.4R2-S6, 24.2 to < 24.2R2-S3, 24.4 to < 24.4R2-S1, 25.2 to < 25.2R1-S1, 25.2R2SRX Series, MX Series with MX-SPC3, MX Series with MS-MPC

06 References

supportportal.juniper.nethttps://supportportal.juniper.net/JSA106004vendor-advisory
kb.juniper.nethttps://kb.juniper.net/JSA106004vendor-advisory

07 Remediation

The following software releases have been updated to resolve this specific issue: 21.2R3-S10, 21.4R3-S12, 22.4R3-S8, 23.2R2-S5, 23.4R2-S6, 24.2R2-S3, 24.4R2-S1, 25.2R1-S1, 25.2R2, 25.4R1, and all subsequent releases.