CVE-2025-59960
Published: 15 January 2026
Summary
CVE-2025-59960 is a high-severity Improper Check for Unusual or Exceptional Conditions (CWE-754) vulnerability in Juniper Junos. Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Service Exhaustion Flood (T1499.002); ranked at the 1.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Requires detection and response to audit logging failures as an unusual or exceptional condition.
Implements detection of unusual or exceptional conditions followed by safe mode entry, reducing the window for exploitation of unchecked conditions.
Training ensures users perform required checks for unusual or exceptional conditions as part of contingency roles, limiting attacker leverage from skipped validations.
IR testing directly validates checks for unusual or exceptional conditions that could indicate security incidents.
Requires ongoing monitoring of organization-defined metrics and analysis, enabling checks for unusual or exceptional conditions.
Security testing routinely checks for unusual or exceptional inputs/conditions, identifying missing validation steps that flaw remediation then resolves.
Requires detection of unusual conditions followed by a controlled transition to the defined failure state.
MTTF determination forces explicit checks for conditions that precede predictable component failure.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability in DHCP relay enables crafted Option 82 packets that directly cause address pool exhaustion on the server, matching Service Exhaustion Flood.
NVD Description
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…
more
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.
Deeper analysisAI
CVE-2025-59960 is an Improper Check for Unusual or Exceptional Conditions vulnerability (CWE-754) in the Juniper DHCP service (jdhcpd) of Juniper Networks Junos OS and Junos OS Evolved. The flaw affects numerous versions, including all Junos OS releases prior to 21.2R3-S10, versions from 21.4 prior to 21.4R3-S12, all 22.2 versions, and ranges in later branches up to 25.2R2 such as 22.4 prior to 22.4R3-S8, 23.2 prior to 23.2R2-S5, and others; similar version ranges apply to Junos OS Evolved. By default, the DHCP relay agent inserts its own Option 82 information when forwarding client requests, but in 'forward-only' mode, it fails to drop specific DHCP DISCOVER packets containing Option 82 unless 'trust-option82' is configured, instead forwarding them unmodified to the DHCP server.
An attacker with adjacent network access (AV:A) and no privileges (PR:N) can exploit this by sending crafted DHCP DISCOVER packets with Option 82 from one subnet. The relay agent forwards these unmodified to the downstream DHCP server, causing it to allocate addresses from unintended pools and exhaust those of other subnets. This results in a high-impact Denial of Service (DoS) on the DHCP server (A:H, scope changed S:C), with a CVSS v3.1 base score of 7.4.
The Juniper security advisory at https://kb.juniper.net/JSA103149 details fixed versions for mitigation, recommending upgrades to patched releases such as Junos OS 21.2R3-S10 or later in the respective branches, and equivalent Junos OS Evolved versions like 21.4R3-S12-EVO. Additional guidance is available via https://supportportal.juniper.net/.
Details
- CWE(s)