CVE-2021-0266

Name: CVE-2021-0266
Creator: NVD / NIST
Published: 2021-04-22T20:15:09.877+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 0.88%

Last modified Jun 17, 2026

CVE-2021-0266 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. The use of multiple hard-coded cryptographic keys in cSRX Series software in Juniper Networks Junos OS allows an attacker to take control of any instance of a cSRX deployment through device management services. This issue affects: Juniper Networks Junos OS on cSRX Series: All versions prior to 20.2R3; 20.3 versions prior to 20.3R2; 20.4 versions prior to 20.4R2.. EPSS estimates a 0.88% chance of exploitation in the next 30 days.

Description

The use of multiple hard-coded cryptographic keys in cSRX Series software in Juniper Networks Junos OS allows an attacker to take control of any instance of a cSRX deployment through device management services. This issue affects: Juniper Networks Junos OS on cSRX Series: All versions prior to 20.2R3; 20.3 versions prior to 20.3R2; 20.4 versions prior to 20.4R2.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

0.88%

54.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Juniper	Junos	20.2	R1
Juniper	Junos	20.3	R1
Juniper	Junos	20.4	R1

References

https://kb.juniper.net/JSA11157Vendor Advisory
https://kb.juniper.net/JSA11157Vendor Advisory

Timeline

Published: Apr 22, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-0266?

How severe is CVE-2021-0266?

CVE-2021-0266 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.88% probability of exploitation in the next 30 days.

How do I fix CVE-2021-0266?

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.

Are you affected by CVE-2021-0266?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST