Junos OS (SRX firewalls)
CVE-2025-30646: Receipt of a malformed LLDP TLV results in l2cpd crash
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).
Published
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 | 21.2R3-S9 or later |
| Junos OS 21.4 | 21.4R3-S10 or later |
| Junos OS 22.2 | 22.2R3-S6 or later |
| Junos OS 22.4 | 22.4R3-S6 or later |
| Junos OS 23.2 | 23.2R2-S3 or later |
| Junos OS 23.4 | 23.4R2-S4 or later |
| Junos OS 24.2 | 24.2R2 or later |
| Junos OS Evolved 0 | 21.4R3-S10-EVO or later |
| Junos OS Evolved 22.2-EVO | 22.2R3-S6-EVO or later |
| Junos OS Evolved 22.4-EVO | 22.4R3-S6-EVO or later |
| Junos OS Evolved 23.2-EVO | 23.2R2-S3-EVO or later |
| Junos OS Evolved 23.4-EVO | 23.4R2-S4-EVO or later |
| Junos OS Evolved 24.2-EVO | 24.2R2-EVO or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Am I affected?
Only systems configured for LLDP with active telemetry subscriptions are vulnerable to this issue:
[ protocols lldp ]
and:
[ system services extension-service request-response ]
Workarounds
There are no known workarounds for this issue.
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 13 Oct 2026.