CVE-2021-31351

HighCVSS 7.5/10Last modified Jun 17, 2026

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;

Metrics

CVSS 3.1 7.5/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weakness enumeration

Affected software

No affected versions have been published.

Timeline

Published
Oct 19, 2021
Last modified
Jun 17, 2026
NVD status
Modified

Related CVEs from 2021

CVE-2021-313525.3An Information Exposure vulnerability in Juniper Networks SRC Series devices configured for NETCONF over SSH permits the negotiation of weakCVE-2021-313537.5An Improper Handling of Exceptional Conditions vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an attacker to inject CVE-2021-313548.8An Out Of Bounds (OOB) access vulnerability in the handling of responses by a Juniper Agile License (JAL) Client in Juniper Networks Junos OCVE-2021-313555.4A persistent cross-site scripting (XSS) vulnerability in the captive portal graphical user interface of Juniper Networks Junos OS may allow CVE-2021-313567.8A command injection vulnerability in command processing on Juniper Networks Junos OS Evolved allows an attacker with authenticated CLI accesCVE-2021-313577.8A command injection vulnerability in tcpdump command processing on Juniper Networks Junos OS Evolved allows an attacker with authenticated CCVE-2021-313587.8A command injection vulnerability in sftp command processing on Juniper Networks Junos OS Evolved allows an attacker with authenticated CLI CVE-2021-313597.8A local privilege escalation vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows a local, low-privileged user to cause thCVE-2021-313607.1An improper privilege management vulnerability in the Juniper Networks Junos OS and Junos OS Evolved command-line interpreter (CLI) allows aCVE-2021-313615.3An Improper Check for Unusual or Exceptional Conditions vulnerability combined with Improper Handling of Exceptional Conditions in Juniper NCVE-2021-313626.5A Protection Mechanism Failure vulnerability in RPD (routing protocol daemon) of Juniper Networks Junos OS and Junos OS Evolved allows an adCVE-2021-313636.5In an MPLS P2MP environment a Loop with Unreachable Exit Condition vulnerability in the routing protocol daemon (RPD) of Juniper Networks Ju
CVE-2021-31351: High severity, CVSS 7.5 | Vulnix