A Signed to Unsigned Conversion Error vulnerability in the Layer 2 Control Protocol daemon (l2cpd) of Juniper Networks Junos OS and Juniper Networks Junos OS Evolved allows an unauthenticated adjacent attacker sending a specifically malformed LLDP TLV to cause the l2cpd process to crash and restart, causing a Denial of Service (DoS).  Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition.

When an LLDP telemetry subscription is active, receipt of a specifically malformed LLDP TLV causes the l2cpd process to crash and restart.

This issue affects:

Junos OS:

* All versions before 21.2R3-S9, 
* from 21.4 before 21.4R3-S10, 
* from 22.2 before 22.2R3-S6, 
* from 22.4 before 22.4R3-S6, 
* from 23.2 before 23.2R2-S3, 
* from 23.4 before 23.4R2-S4, 
* from 24.2 before 24.2R2; 

Junos OS Evolved: 

* All versions before 21.4R3-S10-EVO,
* from 22.2-EVO before 22.2R3-S6-EVO, 
* from 22.4-EVO before 22.4R3-S6-EVO, 
* from 23.2-EVO before 23.2R2-S3-EVO, 
* from 23.4-EVO before 23.4R2-S4-EVO, 
* from 24.2-EVO before 24.2R2-EVO.