Junos OS: Due to a race condition AgentD process causes a memory corruption and FPC reset

A Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in the AgentD process of Juniper Networks Junos OS allows an attacker who is already causing impact to established sessions which generates counter changes picked up by the AgentD process during telemetry polling, to move the AgentD process into a state where AgentD attempts to reap an already destroyed sensor. This reaping attempt then leads to memory corruption causing the FPC to crash which is a Denial of Service (DoS).

The FPC will recover automatically without user intervention after the crash. This issue affects Junos OS:

• All versions before 21.4R3-S9
• From 22.2 before 22.2R3-S5,
• From 22.3 before 22.3R3-S4,
• From 22.4 before 22.4R3-S3,
• From 23.2 before 23.2R2-S2,
• From 23.4 before 23.4R2.

This issue does not affect Junos OS Evolved.