high
7.5
CWE
696
Advisory Published
Updated

CVE-2021-31379: Junos OS: MX Series: MPC 7/8/9/10/11 cards with MAP-E: PFE halts when an attacker sends malformed IPv4 or IPv6 traffic inside the MAP-E tunnel.

First published: Tue Oct 19 2021(Updated: )

An Incorrect Behavior Order vulnerability in the MAP-E automatic tunneling mechanism of Juniper Networks Junos OS allows an attacker to send certain malformed IPv4 or IPv6 packets to cause a Denial of Service (DoS) to the PFE on the device which is disabled as a result of the processing of these packets. Continued receipt and processing of these malformed IPv4 or IPv6 packets will create a sustained Denial of Service (DoS) condition. This issue only affects MPC 7/8/9/10/11 cards, when MAP-E IP reassembly is enabled on these cards. An indicator of compromise is the output: FPC ["FPC ID" # e.g. "0"] PFE #{PFE ID # e.g. "1"] : Fabric Disabled Example: FPC 0 PFE #1 : Fabric Disabled when using the command: show chassis fabric fpcs An example of a healthy result of the command use would be: user@device-re1> show chassis fabric fpcs Fabric management FPC state: FPC 0 PFE #0 Plane 0: Plane enabled Plane 1: Plane enabled Plane 2: Plane enabled Plane 3: Plane enabled Plane 4: Plane enabled Plane 5: Plane enabled Plane 6: Plane enabled Plane 7: Plane enabled This issue affects: Juniper Networks Junos OS on MX Series with MPC 7/8/9/10/11 cards, when MAP-E IP reassembly is enabled on these cards. 17.2 version 17.2R1 and later versions; 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R2-S12, 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R2-S6, 18.2R3-S3; 18.3 versions prior to 18.3R2-S4, 18.3R3-S1; 18.4 versions prior to 18.4R1-S8, 18.4R2-S5, 18.4R3; 19.1 versions prior to 19.1R1-S6, 19.1R2-S2, 19.1R3; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S5, 19.3R3. This issue does not affect Juniper Networks Junos OS versions prior to 17.2R1.

Credit: sirt@juniper.net

Affected SoftwareAffected VersionHow to fix
Juniper JUNOS=17.2-r1
Juniper JUNOS=17.2-r1-s1
Juniper JUNOS=17.2-r1-s2
Juniper JUNOS=17.2-r1-s3
Juniper JUNOS=17.2-r1-s4
Juniper JUNOS=17.2-r1-s5
Juniper JUNOS=17.2-r1-s6
Juniper JUNOS=17.2-r1-s7
Juniper JUNOS=17.2-r1-s8
Juniper JUNOS=17.2-r2
Juniper JUNOS=17.2-r2-s11
Juniper JUNOS=17.2-r2-s4
Juniper JUNOS=17.2-r2-s6
Juniper JUNOS=17.2-r2-s7
Juniper JUNOS=17.2-r3
Juniper JUNOS=17.2-r3-s1
Juniper JUNOS=17.2-r3-s2
Juniper JUNOS=17.2-r3-s3
Juniper JUNOS=17.2-r3-s4
Juniper JUNOS=17.2x75
Juniper JUNOS=17.2x75
Juniper JUNOS=17.2x75-d100
Juniper JUNOS=17.2x75-d102
Juniper JUNOS=17.2x75-d110
Juniper JUNOS=17.2x75-d50
Juniper JUNOS=17.2x75-d70
Juniper JUNOS=17.2x75-d90
Juniper JUNOS=17.2x75-d91
Juniper JUNOS=17.2x75-d92
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-s1
Juniper JUNOS=17.3-r3-s12
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=17.4
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-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=18.1
Juniper JUNOS=18.1-r
Juniper JUNOS=18.1-r1
Juniper JUNOS=18.1-r2
Juniper JUNOS=18.1-r2-s1
Juniper JUNOS=18.1-r2-s2
Juniper JUNOS=18.1-r2-s4
Juniper JUNOS=18.1-r3
Juniper JUNOS=18.1-r3-s1
Juniper JUNOS=18.1-r3-s10
Juniper JUNOS=18.1-r3-s2
Juniper JUNOS=18.1-r3-s3
Juniper JUNOS=18.1-r3-s4
Juniper JUNOS=18.1-r3-s5
Juniper JUNOS=18.1-r3-s6
Juniper JUNOS=18.1-r3-s7
Juniper JUNOS=18.1-r3-s8
Juniper JUNOS=18.1-r3-s9
Juniper JUNOS=18.2
Juniper JUNOS=18.2-r
Juniper JUNOS=18.2-r1
Juniper JUNOS=18.2-r1
Juniper JUNOS=18.2-r1-s2
Juniper JUNOS=18.2-r1-s3
Juniper JUNOS=18.2-r1-s4
Juniper JUNOS=18.2-r1-s5
Juniper JUNOS=18.2-r2
Juniper JUNOS=18.2-r2-s1
Juniper JUNOS=18.2-r2-s2
Juniper JUNOS=18.2-r2-s3
Juniper JUNOS=18.2-r2-s4
Juniper JUNOS=18.2-r2-s5
Juniper JUNOS=18.2-r3
Juniper JUNOS=18.2-r3-s1
Juniper JUNOS=18.2-r3-s2
Juniper JUNOS=18.3
Juniper JUNOS=18.3-r
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-r3
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=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-r2
Juniper JUNOS=19.1-r2-s1
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=19.3
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 Mx10
Juniper Mx10000
Juniper Mx10003
Juniper Mx10008
Juniper Mx10016
Juniper Mx104
Juniper Mx150
Juniper Mx2008
Juniper Mx2010
Juniper Mx2020
Juniper Mx204
Juniper Mx240
Juniper Mx40
Juniper Mx480
Juniper Mx5
Juniper Mx80
Juniper Mx960

Remedy

The following software releases have been updated to resolve this specific issue: 17.3R3-S9, 17.4R2-S12, 17.4R3-S3, 18.1R3-S11, 18.2R2-S6, 18.2R3-S3, 18.3R2-S4, 18.3R3-S1, 18.4R1-S8, 18.4R2-S5, 18.4R3, 19.1R1-S6, 19.1R2-S2, 19.1R3, 19.2R1-S5, 19.2R2, 19.3R2-S5, 19.3R3, 19.4R1, 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-2021-31379?

    CVE-2021-31379 has a severity rating that can lead to Denial of Service (DoS) for devices running affected versions of Junos OS.

  • How do I fix CVE-2021-31379?

    To fix CVE-2021-31379, upgrade your Junos OS to a patched version as specified in the vendor's recommendations.

  • Which versions of Junos OS are affected by CVE-2021-31379?

    CVE-2021-31379 affects multiple versions of Junos OS, including version 17.2 and later releases up to 19.3.

  • What types of attacks are facilitated by CVE-2021-31379?

    CVE-2021-31379 allows attackers to send malformed packets that can exploit the issue leading to device crashes.

  • Are all Juniper devices vulnerable to CVE-2021-31379?

    No, only specific models and configurations of Juniper devices running the affected versions of Junos OS are vulnerable to CVE-2021-31379.

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