medium
6.5
CWE
200 497
Advisory Published
Updated

CVE-2021-0291: Junos OS and Junos OS Evolved: A vulnerability allows a network based unauthenticated attacker which sends a high rate of specific traffic to cause a partial Denial of Service

First published: Thu Jul 15 2021(Updated: )

An Exposure of System Data vulnerability in Juniper Networks Junos OS and Junos OS Evolved, where a sensitive system-level resource is not being sufficiently protected, allows a network-based unauthenticated attacker to send specific traffic which partially reaches this resource. A high rate of specific traffic may lead to a partial Denial of Service (DoS) as the CPU utilization of the RE is significantly increased. The SNMP Agent Extensibility (agentx) process should only be listening to TCP port 705 on the internal routing instance. External connections destined to port 705 should not be allowed. This issue affects: Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S9; 17.3 versions prior to 17.3R3-S12; 17.4 versions prior to 17.4R2-S13, 17.4R3-S5; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R2-S8; 19.1 versions prior to 19.1R3-S5; 19.2 versions prior to 19.2R3-S2; 19.3 versions prior to 19.3R2-S6, 19.3R3-S2; 19.4 versions prior to 19.4R1-S4, 19.4R2-S4, 19.4R3; 20.1 versions prior to 20.1R2; 20.2 versions prior to 20.2R2; 20.3 versions prior to 20.3R2. Juniper Networks Junos OS Evolved versions prior to 20.3R2-EVO. This issue does not affect Juniper Networks Junos OS versions prior to 13.2R1.

Credit: sirt@juniper.net

Affected SoftwareAffected VersionHow to fix
Juniper Junos=15.1
Juniper Junos=15.1-a1
Juniper Junos=15.1-f
Juniper Junos=15.1-f1
Juniper Junos=15.1-f2
Juniper Junos=15.1-f2-s1
Juniper Junos=15.1-f2-s2
Juniper Junos=15.1-f2-s3
Juniper Junos=15.1-f2-s4
Juniper Junos=15.1-f3
Juniper Junos=15.1-f4
Juniper Junos=15.1-f5
Juniper Junos=15.1-f5-s7
Juniper Junos=15.1-f6
Juniper Junos=15.1-f6-s1
Juniper Junos=15.1-f6-s10
Juniper Junos=15.1-f6-s12
Juniper Junos=15.1-f6-s2
Juniper Junos=15.1-f6-s3
Juniper Junos=15.1-f6-s4
Juniper Junos=15.1-f6-s5
Juniper Junos=15.1-f6-s6
Juniper Junos=15.1-f6-s7
Juniper Junos=15.1-f6-s8
Juniper Junos=15.1-f6-s9
Juniper Junos=15.1-f7
Juniper Junos=15.1-r
Juniper Junos=15.1-r1
Juniper Junos=15.1-r2
Juniper Junos=15.1-r3
Juniper Junos=15.1-r4
Juniper Junos=15.1-r4-s7
Juniper Junos=15.1-r4-s8
Juniper Junos=15.1-r4-s9
Juniper Junos=15.1-r5
Juniper Junos=15.1-r5-s1
Juniper Junos=15.1-r5-s3
Juniper Junos=15.1-r5-s5
Juniper Junos=15.1-r5-s6
Juniper Junos=15.1-r6
Juniper Junos=15.1-r6-s1
Juniper Junos=15.1-r6-s2
Juniper Junos=15.1-r6-s3
Juniper Junos=15.1-r6-s4
Juniper Junos=15.1-r6-s6
Juniper Junos=15.1-r7
Juniper Junos=15.1-r7-s1
Juniper Junos=15.1-r7-s2
Juniper Junos=15.1-r7-s3
Juniper Junos=15.1-r7-s4
Juniper Junos=15.1-r7-s5
Juniper Junos=15.1-r7-s6
Juniper Junos=15.1-r7-s7
Juniper Junos=15.1-r7-s8
Juniper Junos=17.3
Juniper Junos=17.3-r1
Juniper Junos=17.3-r1-s1
Juniper Junos=17.3-r1-s4
Juniper Junos=17.3-r2
Juniper Junos=17.3-r2-s1
Juniper Junos=17.3-r2-s2
Juniper Junos=17.3-r2-s3
Juniper Junos=17.3-r2-s4
Juniper Junos=17.3-r2-s5
Juniper Junos=17.3-r3
Juniper Junos=17.3-r3
Juniper Junos=17.3-r3-s1
Juniper Junos=17.3-r3-s10
Juniper Junos=17.3-r3-s11
Juniper Junos=17.3-r3-s2
Juniper Junos=17.3-r3-s3
Juniper Junos=17.3-r3-s4
Juniper Junos=17.3-r3-s5
Juniper Junos=17.3-r3-s6
Juniper Junos=17.3-r3-s7
Juniper Junos=17.3-r3-s8
Juniper Junos=17.3-r3-s9
Juniper Junos=17.4
Juniper Junos=17.4-r1
Juniper Junos=17.4-r1-s1
Juniper Junos=17.4-r1-s2
Juniper Junos=17.4-r1-s3
Juniper Junos=17.4-r1-s4
Juniper Junos=17.4-r1-s5
Juniper Junos=17.4-r1-s6
Juniper Junos=17.4-r1-s7
Juniper Junos=17.4-r2
Juniper Junos=17.4-r2-s1
Juniper Junos=17.4-r2-s10
Juniper Junos=17.4-r2-s11
Juniper Junos=17.4-r2-s12
Juniper Junos=17.4-r2-s2
Juniper Junos=17.4-r2-s3
Juniper Junos=17.4-r2-s4
Juniper Junos=17.4-r2-s5
Juniper Junos=17.4-r2-s6
Juniper Junos=17.4-r2-s7
Juniper Junos=17.4-r2-s8
Juniper Junos=17.4-r2-s9
Juniper Junos=17.4-r3
Juniper Junos=17.4-r3-s1
Juniper Junos=17.4-r3-s2
Juniper Junos=17.4-r3-s3
Juniper Junos=17.4-r3-s4
Juniper Junos=18.3
Juniper Junos=18.3-r1
Juniper Junos=18.3-r1-s1
Juniper Junos=18.3-r1-s2
Juniper Junos=18.3-r1-s3
Juniper Junos=18.3-r1-s4
Juniper Junos=18.3-r1-s5
Juniper Junos=18.3-r1-s6
Juniper Junos=18.3-r2
Juniper Junos=18.3-r2-s1
Juniper Junos=18.3-r2-s2
Juniper Junos=18.3-r2-s3
Juniper Junos=18.3-r2-s4
Juniper Junos=18.3-r3
Juniper Junos=18.3-r3-s1
Juniper Junos=18.3-r3-s2
Juniper Junos=18.3-r3-s3
Juniper Junos=18.3-r3-s4
Juniper Junos=18.4
Juniper Junos=18.4-r1
Juniper Junos=18.4-r1-s1
Juniper Junos=18.4-r1-s2
Juniper Junos=18.4-r1-s3
Juniper Junos=18.4-r1-s4
Juniper Junos=18.4-r1-s5
Juniper Junos=18.4-r1-s6
Juniper Junos=18.4-r1-s7
Juniper Junos=18.4-r2
Juniper Junos=18.4-r2-s1
Juniper Junos=18.4-r2-s2
Juniper Junos=18.4-r2-s3
Juniper Junos=18.4-r2-s4
Juniper Junos=18.4-r2-s5
Juniper Junos=18.4-r2-s6
Juniper Junos=18.4-r2-s7
Juniper Junos=18.4-r3
Juniper Junos=18.4-r3-s1
Juniper Junos=18.4-r3-s2
Juniper Junos=18.4-r3-s3
Juniper Junos=18.4-r3-s4
Juniper Junos=18.4-r3-s5
Juniper Junos=18.4-r3-s6
Juniper Junos=18.4-r3-s7
Juniper Junos=18.4-r3-s8
Juniper Junos=19.1
Juniper Junos=19.1-r1
Juniper Junos=19.1-r1-s1
Juniper Junos=19.1-r1-s2
Juniper Junos=19.1-r1-s3
Juniper Junos=19.1-r1-s4
Juniper Junos=19.1-r1-s5
Juniper Junos=19.1-r1-s6
Juniper Junos=19.1-r2
Juniper Junos=19.1-r2-s1
Juniper Junos=19.1-r2-s2
Juniper Junos=19.1-r3
Juniper Junos=19.1-r3-s1
Juniper Junos=19.1-r3-s2
Juniper Junos=19.1-r3-s3
Juniper Junos=19.1-r3-s4
Juniper Junos=19.2
Juniper Junos=19.2-r1
Juniper Junos=19.2-r1-s1
Juniper Junos=19.2-r1-s2
Juniper Junos=19.2-r1-s3
Juniper Junos=19.2-r1-s4
Juniper Junos=19.2-r1-s5
Juniper Junos=19.2-r1-s6
Juniper Junos=19.2-r2
Juniper Junos=19.2-r2-s1
Juniper Junos=19.2-r3
Juniper Junos=19.2-r3-s1
Juniper Junos=19.3
Juniper Junos=19.3-r1
Juniper Junos=19.3-r1-s1
Juniper Junos=19.3-r2
Juniper Junos=19.3-r2-s1
Juniper Junos=19.3-r2-s2
Juniper Junos=19.3-r2-s3
Juniper Junos=19.3-r2-s4
Juniper Junos=19.3-r2-s5
Juniper Junos=19.3-r3
Juniper Junos=19.3-r3-s1
Juniper Junos=19.4-r1
Juniper Junos=19.4-r1-s1
Juniper Junos=19.4-r1-s2
Juniper Junos=19.4-r1-s3
Juniper Junos=19.4-r2
Juniper Junos=19.4-r2-s1
Juniper Junos=19.4-r2-s2
Juniper Junos=19.4-r2-s3
Juniper Junos=20.1-r1
Juniper Junos=20.1-r1-s1
Juniper Junos=20.1-r1-s2
Juniper Junos=20.1-r1-s3
Juniper Junos=20.1-r1-s4
Juniper Junos=20.2-r1
Juniper Junos=20.2-r1-s1
Juniper Junos=20.2-r1-s2
Juniper Junos=20.2-r1-s3
Juniper Junos=20.3-r1
Juniper Junos=20.3-r1-s1
Juniper Networks Junos OS=19.2-r1
Juniper Networks Junos OS=19.2-r2
Juniper Networks Junos OS=19.3-r1
Juniper Networks Junos OS=19.3-r2
Juniper Networks Junos OS=19.4-r1
Juniper Networks Junos OS=19.4-r2
Juniper Networks Junos OS=19.4-r2-s1
Juniper Networks Junos OS=20.1
Juniper Networks Junos OS=20.1-r1
Juniper Networks Junos OS=20.1-r1-s1
Juniper Networks Junos OS=20.2
Juniper Networks Junos OS=20.3
Juniper Networks Junos OS=20.3-r1

Remedy

The following software releases have been updated to resolve this specific issue: Junos OS: 15.1R7-S9, 17.3R3-S12, 17.4R2-S13, 17.4R3-S5, 18.3R3-S5, 18.4R2-S8, 19.1R3-S5, 19.2R3-S2, 19.3R2-S6, 19.3R3-S2, 19.4R1-S4, 19.4R2-S4, 19.4R3, 20.1R2, 20.2R2, 20.2R3, 20.3R2, 20.4R1, and all subsequent releases. Junos OS Evolved: 20.3R2-EVO, 20.4R1-EVO, and all subsequent releases.

Never miss a vulnerability like this again

Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.

Read MoreStart Free Trial

Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2021-0291?

    CVE-2021-0291 is classified as a medium-severity vulnerability that allows unauthorized access to sensitive system data in Juniper Networks Junos OS.

  • How do I fix CVE-2021-0291?

    To resolve CVE-2021-0291, users should upgrade their Junos OS to versions that include patches or mitigations released by Juniper Networks.

  • Which versions of Junos OS are affected by CVE-2021-0291?

    CVE-2021-0291 affects multiple versions of Junos OS, including 15.1 and 17.3 through 20.3.

  • Can CVE-2021-0291 be exploited remotely?

    Yes, CVE-2021-0291 can be exploited by network-based attackers to send malicious traffic targeting the vulnerable resource.

  • What impact does CVE-2021-0291 have on Juniper devices?

    CVE-2021-0291 could potentially allow an attacker to access sensitive system-level resources, posing risks to device integrity and security.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2025 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203