CVE-2020-1683: On Juniper Networks Junos OS devices, a specific SNMP OID poll causes a memory leak which over time leads to a kernel crash (vmcore).

On Juniper Networks Junos OS devices, a specific SNMP OID poll causes a memory leak which over time leads to a kernel crash (vmcore).

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 ve

Description from the National Vulnerability Database, published by sirt@juniper.net

What it means for a small business

Junos OS is network equipment or remote-access software: the box between your office and the internet. These are a favorite target because breaking one opens the whole office.

If an IT provider set it up, ask them to confirm the firmware version and the date it was updated. If nobody looks after it, that's the bigger problem.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 1.1%, higher than 64% of CVEs. That’s above average: worth scheduling this week. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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