CVE-2024-21618

Junos OS and Junos OS Evolved: When LLDP is enabled and a malformed LLDP packet is received, l2cpd crashes

MEDIUM
6.5
CVSS Score
Published: April 12, 2024 at 02:55 PM 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
MEDIUM6.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

An Access of Memory Location After End of Buffer vulnerability in the Layer-2 Control Protocols Daemon (l2cpd) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause Denial of Service (DoS). On all Junos OS and Junos OS Evolved platforms, when LLDP is enabled on a specific interface, and a malformed LLDP packet is received, l2cpd crashes and restarts. The impact of the l2cpd crash is reinitialization of STP protocols (RSTP, MSTP or VSTP), and MVRP and ERP. Also, if any services depend on LLDP state (like PoE or VoIP device recognition), then these will also be affected. This issue affects: Junos OS: * from 21.4 before 21.4R3-S4, * from 22.1 before 22.1R3-S4, * from 22.2 before 22.2R3-S2, * from 22.3 before 22.3R2-S2, 22.3R3-S1, * from 22.4 before 22.4R3, * from 23.2 before 23.2R2. Junos OS Evolved: * from 21.4-EVO before 21.4R3-S5-EVO, * from 22.1-EVO before 22.1R3-S4-EVO, * from 22.2-EVO before 22.2R3-S2-EVO, * from 22.3-EVO before 22.3R2-S2-EVO, 22.3R3-S1-EVO, * from 22.4-EVO before 22.4R3-EVO, * from 23.2-EVO before 23.2R2-EVO. This issue does not affect: * Junos OS versions prior to 21.4R1; * Junos OS Evolved versions prior to 21.4R1-EVO.

Affected

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

Vendor states this is fixed in 21.4R1 (unaffected)
Affected range stops below 21.4R3-S4, 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 22.3R2-S2, 22.3R3-S1, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.4R3, so it looks safe — our inference, not a vendor statement
Affected range stops below 23.2R2, so it looks safe — our inference, not a vendor statement
21.4-EVO ≤ v < 21.4R3-S5-EVO22.1-EVO ≤ v < 22.1R3-S4-EVO22.2-EVO ≤ v < 22.2R3-S2-EVO22.3-EVO ≤ v < 22.3R2-S2-EVO, 22.3R3-S1-EVO22.4-EVO ≤ v < 22.4R3-EVO23.2-EVO ≤ v < 23.2R2-EVO21.4-EVO22.1-EVO22.2-EVO22.3-EVO22.4-EVO23.2-EVO
Vendor states this is fixed in 21.4R1-EVO (unaffected)
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 22.3R2-S2-EVO, 22.3R3-S1-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 22.4R3-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 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:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

6.5MEDIUMjuniper
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-788CWE-125

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