Vulnerability in Juniper Junos
CVE-2025-59960
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.
EPSS: 0.002 (15.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
Affected products
- Juniper Junos — versions 21.2, 21.4, 22.2
- Juniper Junos_os_evolved — versions 21.4, 22.2, 22.4
- Juniper Networks Junos Os — versions 0, 21.4, 22.2
- Juniper Networks Junos Os Evolved — versions 0, 22.2, 22.4
Weakness classification (CWE)
References
- sirt@juniper.net (Permissions Required, vendor-advisory)
- sirt@juniper.net (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2025-59960?
- CVE-2025-59960 is a high-severity vulnerability in Juniper Junos, classified under Improper Check for Unusual or Exceptional Conditions. CVSS score: 7.4/10. Published 2026-01-15.
- How severe is CVE-2025-59960?
- High severity. CVSS v3 base score is 7.4 out of 10.