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2020-10 Security Bulletin: Junos OS: Memory leak leads to kernel crash (vmcore) due to SNMP polling (CVE-2020-1683)



Article ID: JSA11080 SECURITY_ADVISORIES Last Updated: 28 Oct 2020Version: 2.0
Product Affected:
This issue affects Junos OS 17.4, 18.1, 18.2, 18.2X75, 18.3, 18.4, 19.1, 19.2, 19.3, 19.4.

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.

The example of minimum config stanza affected by this issue:


Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

This issue has been assigned CVE-2020-1683.


The following software releases have been updated to resolve this specific issue: Junos OS 17.4R3-S1, 18.1R3-S10, 18.2R3-S3, 18.2X75-D41, 18.2X75-D430, 18.2X75-D53, 18.2X75-D60, 18.3R3-S2, 18.4R2-S5, 18.4R3-S1, 19.1R2-S2, 19.1R3, 19.2R1-S5, 19.2R2, 19.3R2-S5, 19.3R3, 19.4R1-S3, 19.4R2, 20.1R1, and all subsequent releases.

This issue is being tracked as 1482379.

Disable SNMP (disabled by default), utilize edge filtering with source-address validation (uRPF, etc.), access control lists (ACLs), and/or SNMPv3 authentication to limit access to the device only from trusted hosts.
Software releases or updates are available for download at
Modification History:
2020-10-14: Initial Publication.
CVSS Score:
7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Severity Level:
Severity Assessment:
Information for how Juniper Networks uses CVSS can be found at KB 16446 "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

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