CVE-2024-21605

Junos OS: SRX 300 Series: Specific link local traffic causes a control plane overload

MEDIUM

6.5

CVSS Score

Published: April 12, 2024 at 02:54 PM UTC

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

6 products affected across 2 vendorsJunosSrx300Srx340

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Severity

MEDIUM6.5

Exploit prediction

EPSS 0.3%

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 SRX 300 Series allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS). Specific valid link-local traffic is not blocked on ports in STP blocked state but is instead sent to the control plane of the device. This leads to excessive resource consumption and in turn severe impact on all control and management protocols of the device. This issue affects Juniper Networks Junos OS: * 21.2 version 21.2R3-S3 and later versions earlier than 21.2R3-S6; * 22.1 version 22.1R3 and later versions earlier than 22.1R3-S4; * 22.2 version 22.2R2 and later versions earlier than 22.2R3-S2; * 22.3 version 22.3R2 and later versions earlier than 22.3R3-S1; * 22.4 versions earlier than 22.4R2-S2, 22.4R3; * 23.2 versions earlier than 23.2R1-S1, 23.2R2. This issue does not affect Juniper Networks Junos OS 21.4R1 and later versions of 21.4.

Affected

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

Junos · Juniper Networks

95%

21.2R3-S3 ≤ v < 21.2R3-S622.1R3 ≤ v < 22.1R3-S422.2R2 ≤ v < 22.2R3-S222.3R2 ≤ v < 22.3R3-S122.4 ≤ v < 22.4R2-S2, 22.4R323.2 ≤ v < 23.2R1-S1, 23.2R221.2 r3-s3 21.2 r3-s4 21.2 r3-s5 21.2R3-S3 22.1 r3 22.1 r3-s1 22.1 r3-s2 22.1 r3-s3 22.1R3 22.2 r2 22.2 r2-s1 22.2 r2-s2 22.2 r3 22.2 r3-s1 22.2R2 22.3 r2 22.3 r2-s1 22.3 r2-s2 22.3 r3 22.3R2 22.4 22.4 r1 22.4 r1-s1 22.4 r1-s2 22.4 r2 22.4 r2-s1 23.2 23.2 r1

Affected range stops below 21.2R3-S6, so it looks safe — our inference, not a vendor statement

Vendor states this is fixed in 21.4 (unaffected)

Affected range stops below 22.1R3-S4, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.2R3-S2, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.3R3-S1, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.4R2-S2, 22.4R3, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.2R1-S1, 23.2R2, so it looks safe — our inference, not a vendor statement

juniper-srx300 (environment) · juniper-srx320 (environment) · juniper-srx340 (environment) · juniper-srx345 (environment) · juniper-srx380 (environment)

Srx300 · Juniperdevice

80%

All versions

Srx320 · Juniperdevice

80%

All versions

Srx340 · Juniperdevice

80%

All versions

Srx345 · Juniperdevice

80%

All versions