CVE-2023-36850 Junos OS: MX Series: An MPC will crash upon receipt of a malformed CFM packet.
An adjacent attacker can crash the MPC by sending malformed CFM packets, causing a sustained denial of service on Juniper MX Series devices.
- 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-2023-36850?
CVE-2023-36850 is a medium-severity denial of service vulnerability in Juniper Junos, 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
An Improper Validation of Specified Index, Position, or Offset in Input vulnerability in the Connectivity Fault Management(CFM) module of Juniper Networks Junos OS on MX Series(except MPC10, MPC11 and LC9600) allows an adjacent attacker on the local broadcast domain to cause a Denial of Service(DoS).
Upon receiving a malformed CFM packet, the MPC crashes. Continued receipt of these packets causes a sustained denial of service. This issue can only be triggered when CFM hasn't been configured.
This issue affects: Juniper Networks Junos OS All versions prior to 19.1R3-S10 on MX Series; 19.2 versions prior to 19.2R3-S7 on MX Series; 19.3 versions prior to 19.3R3-S8 on MX Series; 19.4 versions prior to 19.4R3-S12 on MX Series; 20.1 version 20.1R1 and later versions on MX Series; 20.2 versions prior to 20.2R3-S7 on MX Series; 20.3 version 20.3R1 and later versions on MX Series; 20.4 versions prior to 20.4R3-S7 on MX Series; 21.1 versions prior to 21.1R3-S5 on MX Series; 21.2 versions prior to 21.2R3-S4 on MX Series; 21.3 versions prior to 21.3R3-S4 on MX Series; 21.4 versions prior to 21.4R3-S3 on MX Series; 22.1 versions prior to 22.1R3-S2 on MX Series; 22.2 versions prior to 22.2R3 on MX Series; 22.3 versions prior to 22.3R2, 22.3R3 on MX Series; 22.4 versions prior to 22.4R2 on MX Series.
Weakness: CWE-1285
Which versions are affected by CVE-2023-36850?
It affects 1 product.
Products include Juniper Junos.
How do I fix CVE-2023-36850?
No fix has been published for CVE-2023-36850 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-36850 being exploited?
There is no known exploitation of CVE-2023-36850 in the wild and no public exploit code.
Other vulnerabilities in Juniper Junos
- CVE-2023-36845 Juniper Junos OS EX Series and SRX Series PHP External Variable Modification
- CVE-2020-1631 Juniper Junos OS Path Traversal
- CVE-2025-21590 Juniper Junos OS Improper Isolation or Compartmentalization
- CVE-2023-36851 Juniper Junos OS SRX Series Missing Authentication for Critical Function
- CVE-2023-36844 Juniper Junos OS EX Series PHP External Variable Modification
Sources
Also known as GHSA-386p-7ccc-jwxx.