title: Junos OS: Denial of service in telnetd
description: A denial of service vulnerability in the telnetd service on Junos OS allows remote unauthenticated users to cause high CPU usage which may affect system performance. Affected releases are Juniper Networks Junos OS: 12.1X46 versions prior to 12.1X46-D81 on SRX Series; 12.3 versions prior to 12.3R12-S11; 12.3X48 versions prior to 12.3X48-D80 on SRX Series; 15.1 versions prior to 15.1R7; 15.1X49 versions prior to 15.1X49-D150, 15.1X49-D160 on SRX Series; 15.1X53 versions prior to 15.1X53-D59 on EX2300/EX3400 Series; 15.1X53 versions prior to 15.1X53-D68 on QFX10K Series; 15.1X53 versions prior to 15.1X53-D235 on QFX5200/QFX5110 Series; 15.1X53 versions prior to 15.1X53-D495 on NFX Series; 16.1 versions prior to 16.1R4-S12, 16.1R6-S6, 16.1R7; 16.2 versions prior to 16.2R2-S7, 16.2R3; 17.1 versions prior to 17.1R2-S9, 17.1R3; 17.2 versions prior to 17.2R2-S6, 17.2R3; 17.2X75 versions prior to 17.2X75-D100; 17.3 versions prior to 17.3R2-S4, 17.3R3; 17.4 versions prior to 17.4R1-S5, 17.4R2; 18.2X75 versions prior to 18.2X75-D5.
problem types: denial of service
affected:
{
platforms: SRX Series
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 12.1X46-D81, status: affected, version: 12.1X46, versionType: custom
lessThan: 12.3X48-D80, status: affected, version: 12.3X48, versionType: custom
lessThan: 15.1X49-D150, 15.1X49-D160, status: affected, version: 15.1X49, versionType: custom
}
{
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 12.3R12-S11, status: affected, version: 12.3, versionType: custom
lessThan: 15.1R7, status: affected, version: 15.1, versionType: custom
lessThan: 16.1R4-S12, 16.1R6-S6, 16.1R7, status: affected, version: 16.1, versionType: custom
lessThan: 16.2R2-S7, 16.2R3, status: affected, version: 16.2, versionType: custom
lessThan: 17.1R2-S9, 17.1R3, status: affected, version: 17.1, versionType: custom
lessThan: 17.2R2-S6, 17.2R3, status: affected, version: 17.2, versionType: custom
lessThan: 17.2X75-D100, status: affected, version: 17.2X75, versionType: custom
lessThan: 17.3R2-S4, 17.3R3, status: affected, version: 17.3, versionType: custom
lessThan: 17.4R1-S5, 17.4R2, status: affected, version: 17.4, versionType: custom
lessThan: 18.2X75-D5, status: affected, version: 18.2X75, versionType: custom
}
{
platforms: EX2300/EX3400 Series
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 15.1X53-D59, status: affected, version: 15.1X53, versionType: custom
}
{
platforms: QFX10K Series
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 15.1X53-D68, status: affected, version: 15.1X53, versionType: custom
}
{
platforms: QFX5200/QFX5110 Series
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 15.1X53-D235, status: affected, version: 15.1X53, versionType: custom
}
{
platforms: NFX Series
product: Junos OS
vendor: Juniper Networks
versions:
lessThan: 15.1X53-D495, status: affected, version: 15.1X53, versionType: custom
}
metrics:
cvssV3_0: [
attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: LOW
baseScore: 5.3
baseSeverity: MEDIUM
confidentialityImpact: NONE
integrityImpact: NONE
privilegesRequired: NONE
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
version: 3.0
]
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: 12.1X46-D81, 12.3R12-S11, 12.3R13, 12.3X48-D80, 15.1R7, 15.1X49-D150, 15.1X49-D160, 15.1X53-D235, 15.1X53-D495, 15.1X53-D59, 15.1X53-D68, 16.1R4-S12, 16.1R6-S6, 16.1R7, 16.2R2-S7, 16.2R3, 17.1R2-S9, 17.1R3, 17.2R2-S6, 17.2R3, 17.2X75-D100, 17.2X75-D110, 17.3R2-S4, 17.3R3, 17.4R1-S5, 17.4R2, 18.1R1, 18.1R2, 18.2R1, 18.2X75-D5, and all subsequent releases.
workarounds: Disabling the telnet service will completely mitigate this issue.