CVE-2021-31351

HIGH

Juniper Junos OS - Denial of Service via MS-MPC/MS-MIC Packet Processing

Title source: llm
STIX 2.1

Description

An Improper Check for Unusual or Exceptional Conditions in packet processing on the MS-MPC/MS-MIC utilized by Juniper Networks Junos OS allows a malicious attacker to send a specific packet, triggering the MS-MPC/MS-MIC to reset, causing a Denial of Service (DoS). Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue only affects specific versions of Juniper Networks Junos OS on MX Series: 17.3R3-S11; 17.4R2-S13; 17.4R3 prior to 17.4R3-S5; 18.1R3-S12; 18.2R2-S8, 18.2R3-S7, 18.2R3-S8; 18.3R3-S4; 18.4R3-S7; 19.1R3-S4, 19.1R3-S5; 19.2R1-S6; 19.3R3-S2; 19.4R2-S4, 19.4R2-S5; 19.4R3-S2; 20.1R2-S1; 20.2R2-S2, 20.2R2-S3, 20.2R3; 20.3R2, 20.3R2-S1; 20.4R1, 20.4R1-S1, 20.4R2; 21.1R1; This issue does not affect any version of Juniper Networks Junos OS prior to 15.1X49-D240;

References (1)

Core 1
Core References
Vendor Advisory x_refsource_confirm
https://kb.juniper.net/JSA11216

Scores

CVSS v3 7.5
EPSS 0.0039
EPSS Percentile 60.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-754
Status published
Products (15)
juniper/junos 17.3 r3-s11
juniper/junos 17.4 r2-s13 (6 CPE variants)
juniper/junos 18.1 r3-s12
juniper/junos 18.2 r2-s8 (3 CPE variants)
juniper/junos 18.3 r3-s4
juniper/junos 18.4 r3-s7
juniper/junos 19.1 r3-s4 (2 CPE variants)
juniper/junos 19.2 r1-s6
juniper/junos 19.3 r3-s2
juniper/junos 19.4 r2-s4 (3 CPE variants)
... and 5 more
Published Oct 19, 2021
Tracked Since Feb 18, 2026