An Uncontrolled Resource Consumption vulnerability in the kernel of Juniper Networks Junos OS allows an unauthenticated network based attacker to cause 100% CPU load and the device to become unresponsive by sending a flood of traffic to the out-of-band management ethernet port.

Continued receipted of a flood will create a sustained Denial of Service (DoS) condition. Once the flood subsides the system will recover by itself.

An indication that the system is affected by this issue would be that an irq handled by the fman process is shown to be using a high percentage of CPU cycles like in the following example output:

user@host> show system processes extensive
...
PID USERNAME PRI NICE SIZE RES STATE TIME WCPU COMMAND
31 root -84 -187 0K 16K WAIT 22.2H 56939.26% irq96: fman0

This issue affects Juniper Networks Junos OS:

• All versions prior to 18.3R3-S6;
• 18.4 versions prior to 18.4R2-S9, 18.4R3-S9;
• 19.1 versions prior to 19.1R2-S3, 19.1R3-S7;
• 19.2 versions prior to 19.2R1-S7, 19.2R3-S3;
• 19.3 versions prior to 19.3R2-S7, 19.3R3-S4;
• 19.4 versions prior to 19.4R2-S5, 19.4R3-S5;
• 20.1 versions prior to 20.1R3-S1;
• 20.2 versions prior to 20.2R3-S2;
• 20.3 versions prior to 20.3R3-S1;
• 20.4 versions prior to 20.4R2-S2, 20.4R3;
• 21.1 versions prior to 21.1R2;
• 21.2 versions prior to 21.2R1-S1, 21.2R2.

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

This issue has been assigned  CVE-2022-22161 .

The following software releases have been updated to resolve this specific issue: 18.3R3-S6, 18.4R2-S9, 18.4R3-S9, 19.1R2-S3, 19.1R3-S7, 19.2R1-S7, 19.2R3-S3, 19.3R2-S7, 19.3R3-S4, 19.4R2-S5, 19.4R3-S5, 20.1R3-S1, 20.2R3-S2, 20.3R3-S1, 20.4R2-S2, 20.4R3, 21.1R2, 21.2R1-S1, 21.2R2, 21.3R1, and all subsequent releases.

This issue is being tracked as  1585829 .

There are no viable workarounds for this issue.