title: Junos OS: MX Series: Receipt of malformed TCP traffic will cause a Denial of Service
description:
An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on MX Series allows a unauthenticated network-based attacker to cause an infinite loop, resulting in a Denial of Service (DoS).
An attacker who sends malformed TCP traffic via an interface configured with PPPoE, causes an infinite loop on the respective PFE. This results in consuming all resources and a manual restart is needed to recover.
This issue affects interfaces with PPPoE configured and tcp-mss enabled.
This issue affects Juniper Networks Junos OS
*  All versions prior to 20.4R3-S7;
*  21.1 version 21.1R1 and later versions;
*  21.2 versions prior to 21.2R3-S6;
*  21.3 versions prior to 21.3R3-S5;
*  21.4 versions prior to 21.4R3-S3;
*  22.1 versions prior to 22.1R3-S4;
*  22.2 versions prior to 22.2R3;
*  22.3 versions prior to 22.3R2-S2;
*  22.4 versions prior to 22.4R2;
problem types:  CWE-400: Uncontrolled Resource Consumption
affected:
{
defaultStatus: unaffected
platforms: MX Series
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 20.4R3-S7, status: affected, version: 0, versionType: semver
lessThan: 21.1*, status: affected, version: 21.1R1, versionType: semver
lessThan: 21.2R3-S6, status: affected, version: 21.2, versionType: semver
lessThan: 21.3R3-S5, status: affected, version: 21.3, versionType: semver
lessThan: 21.4R3-S3, status: affected, version: 21.4, versionType: semver
lessThan: 22.1R3-S4, status: affected, version: 22.1, versionType: semver
lessThan: 22.2R3, status: affected, version: 22.2, versionType: semver
lessThan: 22.3R2-S2, 22.3R3, status: affected, version: 22.3, versionType: semver
lessThan: 22.4R2, status: affected, version: 22.4, versionType: semver
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: HIGH
baseScore: 7.5
baseSeverity: HIGH
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
version: 3.1
]
format: CVSS
scenarios: GENERAL
exploits: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
solutions: The following software releases have been updated to resolve this specific issue: Junos OS 20.4R3-S7, 21.2R3-S6, 21.4R3-S3, 22.1R3-S4, 22.2R3, 22.3R2-S2, 22.3R3, 22.4R2, 23.2R1, and all subsequent releases.
workarounds: There are no known workarounds for this issue.