CVE-2023-36833

/// Technical description

A Use After Free vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS Evolved on PTX10001-36MR, and PTX10004, PTX10008, PTX10016 with LC1201/1202 allows an adjacent, unauthenticated attacker to cause a Denial of Service (DoS).

The process 'aftman-bt' will crash after multiple flaps on a multicast-only fast reroute (MoFRR) enabled interface. This will cause the respective FPC to stop forwarding traffic and it needs to be rebooted to restore the service.

An indication that the system experienced this issue is the following log message:

  <date> <hostname> evo-aftmand-bt[<pid>]: [Error] jexpr_fdb: sanity check failed, ... , app_name L3 Mcast Routes

This issue affects Juniper Networks Junos OS Evolved on PTX10001-36MR, PTX10004, PTX10008, PTX10016 with LC1201/1202:

21.2 version 21.2R1-EVO and later versions;

21.3 version 21.3R1-EVO and later versions;

21.4 versions prior to 21.4R3-S3-EVO;

22.1 version 22.1R1-EVO and later versions;

22.2 versions prior to

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References