CVE-2024-21596

Junos OS and Junos OS Evolved: A specific BGP UPDATE message will cause a crash in the backup Routing Engine in NSR-enabled devices

MEDIUM

5.3

CVSS Score

Published: January 12, 2024 at 12:52 AM UTC

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

3 products affected across 2 vendorsJunosJunos OS EvolvedJunos OS Evolved

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Severity

MEDIUM5.3

Exploit prediction

EPSS 0.5%

SSVC

No known exploit

Description

A Heap-based Buffer Overflow vulnerability in the Routing Protocol Daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, network based attacker to cause a Denial of Service (DoS). If an attacker sends a specific BGP UPDATE message to the device, this will cause a memory overwrite and therefore an RPD crash and restart in the backup Routing Engine (RE). Continued receipt of these packets will cause a sustained Denial of Service (DoS) condition in the backup RE. The primary RE is not impacted by this issue and there is no impact on traffic. This issue only affects devices with NSR enabled. Note: NSR is not supported on the SRX Series and is therefore not affected by this vulnerability. This issue requires an attacker to have an established BGP session to a system affected by the issue. This issue affects both eBGP and iBGP implementations. This issue affects: Juniper Networks Junos OS * All versions earlier than 20.4R3-S9; * 21.2 versions earlier than 21.2R3-S7; * 21.3 versions earlier than 21.3R3-S5; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3-S4; * 22.2 versions earlier than 22.2R3-S2; * 22.3 versions earlier than 22.3R3-S1; * 22.4 versions earlier than 22.4R2-S2, 22.4R3; * 23.1 versions earlier than 23.1R2; * 23.2 versions earlier than 23.2R1-S2, 23.2R2. Juniper Networks Junos OS Evolved * All versions earlier than 21.3R3-S5-EVO; * 21.4-EVO versions earlier than 21.4R3-S5-EVO; * 22.1-EVO versions earlier than 22.1R3-S4-EVO; * 22.2-EVO versions earlier than 22.2R3-S2-EVO; * 22.3-EVO versions later than 22.3R1-EVO; * 22.4-EVO versions earlier than 22.4R2-S2-EVO, 22.4R3-EVO; * 23.1-EVO versions earlier than 23.1R2-EVO; * 23.2-EVO versions earlier than 23.2R1-S2-EVO, 23.2R2-EVO.

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-S721.3 ≤ v < 21.3R3-S521.4 ≤ v < 21.4R3-S522.1 ≤ v < 22.1R3-S422.2 ≤ v < 22.2R3-S222.3 ≤ v < 22.3R3-S122.4 ≤ v < 22.4R2-S2, 22.4R323.1 ≤ v < 23.1R223.2 ≤ v < 23.2R1-S2, 23.2R220.4 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 21.2 r3-s3 21.2 r3-s4 21.2 r3-s5 21.2 r3-s6 21.3 21.3 r1 21.3 r1-s1 21.3 r1-s2 21.3 r2 21.3 r2-s1 21.3 r2-s2 21.3 r3 21.3 r3-s1 21.3 r3-s2 21.3 r3-s3 21.3 r3-s4 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 22.1 r3 22.1 r3-s1 22.1 r3-s2 22.1 r3-s3 22.2 22.2 r1 22.2 r1-s1 22.2 r1-s2 22.2 r2 22.2 r2-s1 22.2 r2-s2 22.2 r3 22.2 r3-s1 22.3 22.3 r1 22.3 r1-s1 22.3 r1-s2 22.3 r2 22.3 r2-s1 22.3 r2-s2 22.3 r3 22.4 22.4 r1 22.4 r1-s1 22.4 r1-s2 22.4 r2 22.4 r2-s1 23.1 23.1 r1 23.2 23.2 r1 23.2 r1-s1

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

Affected range stops below 21.2R3-S7, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.3R3-S5, 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-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 23.1R2, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.2R1-S2, 23.2R2, so it looks safe — our inference, not a vendor statement

Junos OS Evolved · Juniper Networks

60%

v < 21.3R3-S5-EVO21.4-EVO ≤ v < 21.4R3-S5-EVO22.1-EVO ≤ v < 22.1R3-S4-EVO22.2-EVO ≤ v < 22.2R3-S2-EVO22.4-EVO ≤ v < 22.4R2-S2-EVO, 22.4R3-EVO23.1-EVO ≤ v < 23.1R2-EVO23.2-EVO ≤ v < 23.2R1-S2-EVO, 23.2R2-EVO21.4-EVO 22.1-EVO 22.2-EVO 22.4-EVO 23.1-EVO 23.2-EVO

Affected range stops below 21.3R3-S5-EVO, so it looks safe — our inference, not a vendor statement

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

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

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

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

Affected range stops below 23.1R2-EVO, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.2R1-S2-EVO, 23.2R2-EVO, 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

References (2)

Vendor Advisory

Source: [email protected]

https://supportportal.juniper.net/JSA75735

Technical DescriptionVendor 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:N/VA:L/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

5.3MEDIUMjuniper

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

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-122CWE-787

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