high
7.5
CWE
400
Advisory Published
Updated

CVE-2023-36841: Junos OS: MX Series: Receipt of malformed TCP traffic will cause a Denial of Service

First published: Thu Oct 12 2023(Updated: )

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on MX Series allows a unauthenticated network-based attacker to cause an infinite loop, resulting in a Denial of Service (DoS). An attacker who sends malformed TCP traffic via an interface configured with PPPoE, causes an infinite loop on the respective PFE. This results in consuming all resources and a manual restart is needed to recover. This issue affects interfaces with PPPoE configured and tcp-mss enabled. This issue affects Juniper Networks Junos OS * All versions prior to 20.4R3-S7; * 21.1 version 21.1R1 and later versions; * 21.2 versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S3; * 22.1 versions prior to 22.1R3-S4; * 22.2 versions prior to 22.2R3; * 22.3 versions prior to 22.3R2-S2; * 22.4 versions prior to 22.4R2;

Credit: sirt@juniper.net

Affected SoftwareAffected VersionHow to fix
Juniper Junos<20.4
Juniper Junos=20.4
Juniper Junos=20.4-r1
Juniper Junos=20.4-r1-s1
Juniper Junos=20.4-r2
Juniper Junos=20.4-r2-s1
Juniper Junos=20.4-r2-s2
Juniper Junos=20.4-r3
Juniper Junos=20.4-r3-s1
Juniper Junos=20.4-r3-s2
Juniper Junos=20.4-r3-s3
Juniper Junos=20.4-r3-s4
Juniper Junos=20.4-r3-s5
Juniper Junos=20.4-r3-s6
Juniper Junos=21.1-r1
Juniper Junos=21.1-r1-s1
Juniper Junos=21.1-r2
Juniper Junos=21.1-r2-s1
Juniper Junos=21.1-r2-s2
Juniper Junos=21.1-r3
Juniper Junos=21.1-r3-s1
Juniper Junos=21.1-r3-s2
Juniper Junos=21.1-r3-s3
Juniper Junos=21.1-r3-s4
Juniper Junos=21.1-r3-s5
Juniper Junos=21.2
Juniper Junos=21.2-r1
Juniper Junos=21.2-r1-s1
Juniper Junos=21.2-r1-s2
Juniper Junos=21.2-r2
Juniper Junos=21.2-r2-s1
Juniper Junos=21.2-r2-s2
Juniper Junos=21.2-r3
Juniper Junos=21.2-r3-s1
Juniper Junos=21.2-r3-s2
Juniper Junos=21.2-r3-s3
Juniper Junos=21.2-r3-s4
Juniper Junos=21.2-r3-s5
Juniper Junos=21.3
Juniper Junos=21.3-r1
Juniper Junos=21.3-r1-s1
Juniper Junos=21.3-r1-s2
Juniper Junos=21.3-r2
Juniper Junos=21.3-r2-s1
Juniper Junos=21.3-r2-s2
Juniper Junos=21.3-r3
Juniper Junos=21.3-r3-s1
Juniper Junos=21.3-r3-s2
Juniper Junos=21.3-r3-s3
Juniper Junos=21.3-r3-s4
Juniper Junos=21.4
Juniper Junos=21.4-r1
Juniper Junos=21.4-r1-s1
Juniper Junos=21.4-r1-s2
Juniper Junos=21.4-r2
Juniper Junos=21.4-r2-s1
Juniper Junos=21.4-r2-s2
Juniper Junos=21.4-r3
Juniper Junos=21.4-r3-s1
Juniper Junos=21.4-r3-s2
Juniper Junos=22.1-r1
Juniper Junos=22.1-r1-s1
Juniper Junos=22.1-r1-s2
Juniper Junos=22.1-r2
Juniper Junos=22.1-r2-s1
Juniper Junos=22.1-r2-s2
Juniper Junos=22.1-r3
Juniper Junos=22.1-r3-s1
Juniper Junos=22.1-r3-s2
Juniper Junos=22.1-r3-s3
Juniper Junos=22.2-r1
Juniper Junos=22.2-r1-s1
Juniper Junos=22.2-r1-s2
Juniper Junos=22.2-r2
Juniper Junos=22.2-r2-s1
Juniper Junos=22.2-r2-s2
Juniper Junos=22.3-r1
Juniper Junos=22.3-r1-s1
Juniper Junos=22.3-r1-s2
Juniper Junos=22.3-r2
Juniper Junos=22.3-r2-s1
Juniper Junos=22.4-r1
Juniper Junos=22.4-r1-s1
Juniper Junos=22.4-r1-s2

Remedy

The following software releases have been updated to resolve this specific issue: Junos OS 20.4R3-S7, 21.2R3-S6, 21.4R3-S3, 22.1R3-S4, 22.2R3, 22.3R2-S2, 22.3R3, 22.4R2, 23.2R1, and all subsequent releases.

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2023-36841?

    The severity of CVE-2023-36841 is classified as high due to its potential to cause a Denial of Service (DoS) via an infinite loop.

  • How do I fix CVE-2023-36841?

    To resolve CVE-2023-36841, upgrade to a fixed version of Junos OS as outlined in Juniper's security advisories.

  • Which versions of Junos OS are affected by CVE-2023-36841?

    Versions of Junos OS affected by CVE-2023-36841 include those prior to 20.4 and several specific versions up to 22.4.

  • What are the potential impacts of CVE-2023-36841?

    The potential impacts of CVE-2023-36841 include causing an infinite loop that results in Denial of Service conditions.

  • Is CVE-2023-36841 exploitable remotely?

    Yes, CVE-2023-36841 can be exploited by an unauthenticated network-based attacker.

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