CVE-2020-1637: A vulnerability in Juniper Networks SRX Series device configured as a Junos OS Enforcer device may allow a user to access network resources that are n...

Description

A vulnerability in Juniper Networks SRX Series device configured as a Junos OS Enforcer device may allow a user to access network resources that are not permitted by a UAC policy. This issue might occur when the IP address range configured in the Infranet Controller (IC) is configured as an IP address range instead of an IP address/netmask. See the Workaround section for more detail. The Junos OS Enforcer CLI settings are disabled by default. This issue affects Juniper Networks Junos OS on SRX Series: 12.3X48 versions prior to 12.3X48-D100; 15.1X49 versions prior to 15.1X49-D210; 17.3 versions prior to 17.3R2-S5, 17.3R3-S8; 17.4 versions prior to 17.4R2-S9, 17.4R3-S1; 18.1 versions prior to 18.1R3-S10; 18.2 versions prior to 18.2R2-S7, 18.2R3-S3; 18.3 versions prior to 18.3R1-S7, 18.3R3-S2; 18.4 versions prior to 18.4R1-S6, 18.4R2-S4, 18.4R3-S1; 19.1 versions prior to 19.1R1-S4, 19.1R2-S1, 19.1R3; 19.2 versions prior to 19.2R1-S3, 19.2R2; 19.3 versions prior to 19.3R2-S1, 19.3R3; 19.4 versions prior to 19.4R1-S1, 19.4R2.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS Probability

0.81%

52.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Juniper	Junos	12.3x48	—
Juniper	Junos	15.1x49	—
Juniper	Junos	17.3	—
Juniper	Junos	17.4	—
Juniper	Junos	18.1	—
Juniper	Junos	18.2	—
Juniper	Junos	18.3	—
Juniper	Junos	18.4	—
Juniper	Junos	19.1	—
Juniper	Junos	19.2	—
Juniper	Junos	19.3	R2
Juniper	Junos	19.4	R1

References

https://kb.juniper.net/JSA11018Vendor Advisory
https://kb.juniper.net/JSA11018Vendor Advisory

Timeline

Published: Apr 8, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-1637?

A vulnerability in Juniper Networks SRX Series device configured as a Junos OS Enforcer device may allow a user to access network resources that are not permitted by a UAC policy. This issue might occur when the IP address range configured in the Infranet Controller (IC) is configured as an IP address range instead of an IP address/netmask. See the Workaround section for more detail. The Junos OS Enforcer CLI settings are disabled by default. This issue affects Juniper Networks Junos OS on SRX Series: 12.3X48 versions prior to 12.3X48-D100; 15.1X49 versions prior to 15.1X49-D210; 17.3 versions prior to 17.3R2-S5, 17.3R3-S8; 17.4 versions prior to 17.4R2-S9, 17.4R3-S1; 18.1 versions prior to 18.1R3-S10; 18.2 versions prior to 18.2R2-S7, 18.2R3-S3; 18.3 versions prior to 18.3R1-S7, 18.3R3-S2; 18.4 versions prior to 18.4R1-S6, 18.4R2-S4, 18.4R3-S1; 19.1 versions prior to 19.1R1-S4, 19.1R2-S1, 19.1R3; 19.2 versions prior to 19.2R1-S3, 19.2R2; 19.3 versions prior to 19.3R2-S1, 19.3R3; 19.4 versions prior to 19.4R1-S1, 19.4R2.

How severe is CVE-2020-1637?

CVE-2020-1637 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.81% probability of exploitation in the next 30 days.

How do I fix CVE-2020-1637?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.