DHCP pool exhaustion via unfiltered Option 82
Published Jan 15, 2026 · Updated Jan 15, 2026
Improper condition handling in jdhcpd in Junos OS and Junos OS Evolved allows adjacent attackers to exhaust downstream DHCP address pools. In forward-only mode, the relay forwards a client's Option 82-bearing DHCP DISCOVER unchanged instead of dropping it when trust-option82 is absent. A DHCP client on one subnet can consume leases assigned to other subnets, leaving the downstream server unable to issue those addresses.
Summary
What happened
Improper condition handling in jdhcpd in Junos OS and Junos OS Evolved allows adjacent attackers to exhaust downstream DHCP address pools. In forward-only mode, the relay forwards a client's Option 82-bearing DHCP DISCOVER unchanged instead of dropping it when trust-option82 is absent. A DHCP client on one subnet can consume leases assigned to other subnets, leaving the downstream server unable to issue those addresses.
The record
- CVE
- CVE-2025-59960
- Published
- Jan 15, 2026
- Updated
- Jan 15, 2026
- Vendor
- Juniper Networks
- Product
- Junos OS Evolved
- Classifications
- CWE-754, T1499.003
- Attack vector
- adjacent
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 15, 2026CVE publishedPublication date reported by the CVE source.
- Jan 15, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <21.4R3-S12-EVO
- Affected versionversion=22.2 <22.2*
- Affected versionversion=22.4 <22.4R3-S8-EVO
- Affected versionversion=23.2 <23.2R2-S5-EVO
- Affected versionversion=23.4 <23.4R2-S6-EVO
- Affected versionversion=24.2 <24.2R2-S2-EVO
- Affected versionversion=24.4 <24.4R2-EVO
- Affected versionversion=25.2 <25.2R1-S1-EVO, 25.2R2-EVO
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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