CVE-2020-1683 Junos OS: Memory leak leads to kernel crash (vmcore) due to SNMP polling
Attackers can cause a kernel crash and service outage on Juniper Junos devices by triggering a memory leak via specific SNMP polling.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2020-1683?
CVE-2020-1683 is a high-severity denial of service vulnerability in Juniper Junos, published on 16 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
On Juniper Networks Junos OS devices, a specific SNMP OID poll causes a memory leak which over time leads to a kernel crash (vmcore). Prior to the kernel crash other processes might be impacted, such as failure to establish SSH connection to the device. The administrator can monitor the output of the following command to check if there is memory leak caused by this issue: user@device> show system virtual-memory | match "pfe_ipc|kmem" pfe_ipc 147 5K - 164352 16,32,64,8192 <-- increasing vm.kmem_map_free: 127246336 <-- decreasing pfe_ipc 0 0K - 18598 32,8192 vm.kmem_map_free: 134582272 This issue affects Juniper Networks Junos OS: 17.4R3; 18.1 version 18.1R3-S5 and later versions prior to 18.1R3-S10; 18.2 version 18.2R3 and later versions prior to 18.2R3-S3; 18.2X75 version 18.2X75-D420, 18.2X75-D50 and later versions prior to 18.2X75-D430, 18.2X75-D53, 18.2X75-D60; 18.3 version 18.3R3 and later versions prior to 18.3R3-S2; 18.4 version 18.4R1-S4, 18.4R2 and later versions prior to 18.4R2-S5, 18.4R3-S1; 19.1 version 19.1R2 and later versions prior to 19.1R2-S2, 19.1R3; 19.2 version 19.2R1 and later versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S5, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2. This issue does not affect Juniper Networks Junos OS prior to 17.4R3.
Weakness: CWE-401
Which versions are affected by CVE-2020-1683?
It affects 1 product.
Products include Juniper Junos.
How do I fix CVE-2020-1683?
No fix has been published for CVE-2020-1683 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-2020-1683 being exploited?
There is no known exploitation of CVE-2020-1683 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-h8g9-274c-2qqg.