CVE-2023-36833 Use after free in Junos OS Evolved
An adjacent attacker can cause a denial of service by triggering a use-after-free crash in the PFE during MoFRR link flaps.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2023-36833?
CVE-2023-36833 is a medium-severity use after free vulnerability in Juniper Junos Os Evolved, published on 14 Jul 2023. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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 22.2R3-S2-EVO; 22.3 versions prior to 22.3R3-EVO; 22.4 versions prior to 22.4R1-S2-EVO, 22.4R2-EVO.
Weakness: CWE-416
Which versions are affected by CVE-2023-36833?
It affects 1 product.
Products include Juniper Junos Os Evolved.
How do I fix CVE-2023-36833?
No fix has been published for CVE-2023-36833 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2023-36833 being exploited?
There is no known exploitation of CVE-2023-36833 in the wild and no public exploit code.
Other vulnerabilities in Juniper Junos Os Evolved
- CVE-2026-21902 Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root
- CVE-2023-28983 Junos OS Evolved: Shell Injection vulnerability in the gNOI server
- CVE-2025-21599 Denial of service in Junos OS Evolved
- CVE-2024-47502 Junos OS Evolved: TCP session state is not always cleared on the Routing Engine leading to DoS
- CVE-2024-39531 Junos OS Evolved: ACX 7000 Series: Protocol specific DDoS configuration affects other protocols
Sources
Also known as GHSA-c9pw-fcq9-5p4q.