Junos OS (SRX firewalls)
CVE-2025-59960: DHCP Option 82 messages from clients being passed unmodified to the DHCP server
An Improper Check for Unusual or Exceptional Conditions vulnerability in the Juniper DHCP service (jdhcpd) of Juniper Networks Junos OS and Junos OS Evolved allows a DHCP client in one subnet to exhaust the address pools of other subnets, leading to a Denial of Service (DoS) on the downstream DHCP server.
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-S10 or later |
| Junos OS 21.4 | 21.4R3-S12 or later |
| Junos OS 22.2 | 22.2* or later |
| Junos OS 22.4 | 22.4R3-S8 or later |
| Junos OS 23.2 | 23.2R2-S5 or later |
| Junos OS 23.4 | 23.4R2-S6 or later |
| Junos OS 24.2 | 24.2R2-S2 or later |
| Junos OS 24.4 | 24.4R2 or later |
| Junos OS 25.2 | 25.2R1-S1, 25.2R2 or later |
| Junos OS Evolved 0 | 21.4R3-S12-EVO or later |
| Junos OS Evolved 22.2 | 22.2* or later |
| Junos OS Evolved 22.4 | 22.4R3-S8-EVO or later |
| Junos OS Evolved 23.2 | 23.2R2-S5-EVO or later |
| Junos OS Evolved 23.4 | 23.4R2-S6-EVO or later |
| Junos OS Evolved 24.2 | 24.2R2-S2-EVO or later |
| Junos OS Evolved 24.4 | 24.4R2-EVO or later |
| Junos OS Evolved 25.2 | 25.2R1-S1-EVO, 25.2R2-EVO or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
An Improper Check for Unusual or Exceptional Conditions vulnerability in the Juniper DHCP service (jdhcpd) of Juniper Networks Junos OS and Junos OS Evolved allows a DHCP client in one subnet to exhaust the address pools of other subnets, leading to a Denial of Service (DoS) on the downstream DHCP server.
By default, the DHCP relay agent inserts its own Option 82 information when forwarding client requests, optionally replacing any Option 82 information provided by the client. When a specific DHCP DISCOVER is received in 'forward-only' mode with Option 82, the device should drop the message unless 'trust-option82' is configured. Instead, the DHCP relay forwards these packets to the DHCP server unmodified, which uses up addresses in the DHCP server's address pool, ultimately leading to address pool exhaustion.
This issue affects Junos OS:
- all versions before 21.2R3-S10,
- from 21.4 before 21.4R3-S12,
- all versions of 22.2,
- from 22.4 before 22.4R3-S8,
- from 23.2 before 23.2R2-S5,
- from 23.4 before 23.4R2-S6,
- from 24.2 before 24.2R2-S2,
- from 24.4 before 24.4R2,
- from 25.2 before 25.2R1-S1, 25.2R2.
Junos OS Evolved:
- all versions before 21.4R3-S12-EVO,
- all versions of 22.2-EVO,
- from 22.4 before 22.4R3-S8-EVO,
- from 23.2 before 23.2R2-S5-EVO,
- from 23.4 before 23.4R2-S6-EVO,
- from 24.2 before 24.2R2-S2-EVO,
- from 24.4 before 24.4R2-EVO,
- from 25.2 before 25.2R1-S1-EVO, 25.2R2-EVO.
Am I affected?
DHCP Relay must be configured for forward-only to be vulnerable to this issue:
[ forwarding-options dhcp-relay forward-only ]
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.