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Product Affected

This issue affects Junos OS 21.4R3, 22.2R2, 22.3R1, 22.3R3, 22.4R1, 23.2. Affected platforms: MX Series with MPC10, MPC11, LC9600, MX304.

Severity

Medium

Severity Assessment (CVSS) Score

CVSS 3.1: 6.5 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVSS 4.0: 7.1 (CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N)

Problem

An Improper Check or Handling of Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS).

If an attacker sends a specific MPLS packet, which upon processing, causes an internal loop, that leads to a PFE crash and restart. Continued receipt of these packets leads to a sustained Denial of Service (DoS) condition.

Circuit cross-connect (CCC) needs to be configured on the device for it to be affected by this issue.

This issue only affects Junos OS on MX Series with MPC10, MPC11, LC9600, and MX304.

This issue affects:
Juniper Networks Junos OS
21.4 versions from 21.4R3 earlier than 21.4R3-S5;
22.2 versions from 22.2R2 earlier than 22.2R3-S2;
22.3 versions from 22.3R1 earlier than 22.3R2-S2;
22.3 versions from 22.3R3 earlier than 22.3R3-S1
22.4 versions from 22.4R1 earlier than 22.4R2-S2, 22.4R3;
23.2 versions earlier than 23.2R1-S1, 23.2R2.

This issue does not affect Junos OS 22.1 versions.

To be affected by this issue, the following configuration is required on the device:
[encapsulation ethernet-ccc]

Solution

The following software releases have been updated to resolve this specific issue:

Junos OS: 21.4R3-S5, 22.2R3-S2, 22.2R3-S3, 22.3R2-S2, 22.3R3-S1, 22.4R2-S2, 22.4R3, 23.2R1-S1, 23.2R2, 23.4R1, and all subsequent releases.

This issue is being tracked as 1720275 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

Workaround

There are no known workarounds for this issue.

Severity Assessment

Information for how Juniper Networks uses CVSS can be found at KB 16446 [juniper.net] "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

Modification History