CVE-2024-39557 Junos OS Evolved: MAC table changes cause a memory leak
An unauthenticated adjacent attacker can trigger a memory leak in the Layer 2 Address Learning Daemon, causing system exhaustion and a crash.
- 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-2024-39557?
CVE-2024-39557 is a high-severity denial of service vulnerability in Juniper Junos Os Evolved, published on 10 Jul 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
An Uncontrolled Resource Consumption vulnerability in the
Layer 2 Address Learning Daemon (l2ald)
of Juniper Networks Junos OS Evolved allows an unauthenticated, adjacent attacker to cause a memory leak, eventually exhausting all system memory, leading to a system crash and Denial of Service (DoS).
Certain MAC table updates cause a small amount of memory to leak. Once memory utilization reaches its limit, the issue will result in a system crash and restart.
To identify the issue, execute the CLI command: user@device> show platform application-info allocations app l2ald-agent EVL Object Allocation Statistics: Node Application Context Name Live Allocs Fails Guids re0 l2ald-agent net::juniper::rtnh::L2Rtinfo 1069096 1069302 0 1069302 re0 l2ald-agent net::juniper::rtnh::NHOpaqueTlv 114 195 0 195
This issue affects Junos OS Evolved:
* All versions before 21.4R3-S8-EVO,
* from 22.2-EVO before 22.2R3-S4-EVO, * from 22.3-EVO before 22.3R3-S3-EVO, * from 22.4-EVO before 22.4R3-EVO, * from 23.2-EVO before 23.2R2-EVO.
Weakness: CWE-400
Which versions are affected by CVE-2024-39557?
It affects 1 product.
Products include Juniper Junos Os Evolved.
How do I fix CVE-2024-39557?
No fix has been published for CVE-2024-39557 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-2024-39557 being exploited?
There is no known exploitation of CVE-2024-39557 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-g26w-g327-7xm5.