CVE-2024-39536 Junos OS and Junos OS Evolved: Flaps of BFD sessions with authentication cause a ppmd memory leak
An unauthenticated adjacent attacker can cause a memory leak and denial of service by flapping authenticated BFD sessions in Junos OS.
- 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-2024-39536?
CVE-2024-39536 is a medium-severity denial of service vulnerability in Juniper Junos, published on 11 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A Missing Release of Memory after Effective Lifetime vulnerability in the Periodic Packet Management Daemon (ppmd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker to cause a
Denial-of-Service (DoS).
When a BFD session configured with authentication flaps, ppmd memory can leak. Whether the leak happens depends on a race condition which is outside the attackers control. This issue only affects BFD operating in distributed aka delegated (which is the default behavior) or inline mode.
Whether the leak occurs can be monitored with the following CLI command:
> show ppm request-queue
FPC Pending-request fpc0 2 request-total-pending: 2
where a continuously increasing number of pending requests is indicative of the leak.
This issue affects:
Junos OS:
* All versions before 21.2R3-S8, * 21.4 versions before 21.4R3-S7, * 22.1 versions before 22.1R3-S4, * 22.2 versions before 22.2R3-S4, * 22.3 versions before 22.3R3, * 22.4 versions before 22.4R2-S2, 22.4R3.
Junos OS Evolved: * All versions before 21.2R3-S8-EVO, * 21.4-EVO versions before 21.4R3-S7-EVO, * 22.2-EVO versions before 22.2R3-S4-EVO, * 22.3-EVO versions before 22.3R3-EVO, * 22.4-EVO versions before 22.4R3-EVO.
Weakness: CWE-401
Which versions are affected by CVE-2024-39536?
It affects 2 products.
Products include Juniper Junos, Juniper Junos Os Evolved.
How do I fix CVE-2024-39536?
No fix has been published for CVE-2024-39536 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-2024-39536 being exploited?
There is no known exploitation of CVE-2024-39536 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-vpjj-mfgj-j3mj.