Junos OS (SRX firewalls)
CVE-2026-102051: An attacker causes l2cpd memory exhaustion when LLDP fast receive processing is enabled
An Improper Release of Memory Before Removing Last Reference vulnerability in the l2cpd process of Juniper Networks Junos OS and Junos OS Evolved platforms allows an adjacent unauthenticated attacker to cause l2cpd memory exhaustion and Layer 2 control-plane disruption via LLDP traffic when fast receive processing is enabled.
Published Juniper Networks advisory JSA112187
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Junos OS 0 | 23.2R2-S7.7 or later |
| Junos OS 23.4 | 23.4R2-S8.13 or later |
| Junos OS 24.2 | 24.2R2-S5.5 or later |
| Junos OS 24.4 | 24.4R2-S5 or later |
| Junos OS 25.2 | 25.2R2-S2 or later |
| Junos OS 25.4 | 25.4R1-S3 or later |
| Junos OS 26.2 | 26.2R1-S2 or later |
| Junos OS Evolved 0 | 23.2R2-S7.7-EVO or later |
| Junos OS Evolved 23.4 | 23.4R2-S8.11-EVO or later |
| Junos OS Evolved 24.2 | 24.2R2-S5.6-EVO or later |
| Junos OS Evolved 24.4 | 24.4R2-S5-EVO or later |
| Junos OS Evolved 25.2 | 25.2R2-S2-EVO or later |
| Junos OS Evolved 25.4 | 25.4R1-S3-EVO or later |
| Junos OS Evolved 26.2 | 26.2R1-S2-EVO or later |
| Junos OS Evolved 23.4X100 | See the advisory |
| Junos OS Evolved 25.2X100 | 25.2X100-D35-EVO or later |
| Junos OS Evolved 25.4X300 | 25.4X300-D40-EVO or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
In short
A memory management flaw in the l2cpd process allows an attacker on an adjacent network to exhaust system memory and disrupt Layer 2 control-plane operations. By sending specific LLDP traffic while fast receive processing is enabled, the attacker can trigger this issue without needing to log in or interact with users. This leads to a denial of service for the affected firewall.
Written by a language model from the vendor's description. Versions, fixes and exploitation status on this page come straight from the vendor and CISA.
The vendor's description
An Improper Release of Memory Before Removing Last Reference vulnerability in the l2cpd process of Juniper Networks Junos OS and Junos OS Evolved platforms allows an adjacent unauthenticated attacker to cause l2cpd memory exhaustion and Layer 2 control-plane disruption via LLDP traffic when fast receive processing is enabled.
Am I affected?
[ protocols lldp interface <interface> ] [ protocols lldp fast-rx-processing ]
Workarounds
Do not configure "set protocols lldp fast-rx-processing".
Exploitation
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 19 Oct 2026.