CVE-2024-21597

Junos OS: MX Series: In an AF scenario traffic can bypass configured lo0 firewall filters

HIGH

7.5

CVSS Score

Published: January 12, 2024 at 12:53 AM UTC

Updated: June 17, 2026 at 07:09 AM UTC

1 product affected across 1 vendorJunos

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Severity

HIGH7.5

Exploit prediction

EPSS 0.4%

SSVC

No known exploit

Description

An Exposure of Resource to Wrong Sphere vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass the intended access restrictions. In an Abstracted Fabric (AF) scenario if routing-instances (RI) are configured, specific valid traffic destined to the device can bypass the configured lo0 firewall filters as it's received in the wrong RI context. This issue affects Juniper Networks Junos OS on MX Series: * All versions earlier than 20.4R3-S9; * 21.2 versions earlier than 21.2R3-S3; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3; * 22.2 versions earlier than 22.2R3; * 22.3 versions earlier than 22.3R2.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Junos · Juniper Networks

95%

v < 20.4R3-S921.2 ≤ v < 21.2R3-S321.4 ≤ v < 21.4R3-S522.1 ≤ v < 22.1R322.2 ≤ v < 22.2R322.3 ≤ v < 22.3R220.4 20.4 r1 20.4 r1-s1 20.4 r2 20.4 r2-s1 20.4 r2-s2 20.4 r3 20.4 r3-s1 20.4 r3-s2 20.4 r3-s3 20.4 r3-s4 20.4 r3-s5 20.4 r3-s6 20.4 r3-s7 20.4 r3-s8 21.2 21.2 r1 21.2 r1-s1 21.2 r1-s2 21.2 r2 21.2 r2-s1 21.2 r2-s2 21.2 r3 21.2 r3-s1 21.2 r3-s2 21.4 21.4 r1 21.4 r1-s1 21.4 r1-s2 21.4 r2 21.4 r2-s1 21.4 r2-s2 21.4 r3 21.4 r3-s1 21.4 r3-s2 21.4 r3-s3 21.4 r3-s4 22.1 22.1 r1 22.1 r1-s1 22.1 r1-s2 22.1 r2 22.1 r2-s1 22.1 r2-s2 22.2 22.2 r1 22.2 r1-s1 22.2 r1-s2 22.2 r2 22.2 r2-s1 22.2 r2-s2 22.3 22.3 r1 22.3 r1-s1 22.3 r1-s2

Affected range stops below 20.4R3-S9, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.2R3-S3, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.4R3-S5, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.1R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.2R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.3R2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://supportportal.juniper.net/JSA75738

References (2)

Vendor Advisory

Source: [email protected]

https://supportportal.juniper.net/JSA75738

Technical DescriptionThird Party Advisory

Source: [email protected]

https://www.first.org/cvss/calculator/4.0#CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGH[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: HIGH
Availability: NONE

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-668

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