dbcve.org
JunosOperating system · Juniper

CVE-2025-59960

HIGH · 7.4 CVSS v3.1 Published 2026-01-15
Fix available
A fix is available. Upgrade to 21.2 / 21.4 or later.
See remediation →
79/100
Remediation priority · High
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Juniper DHCP relay (jdhcpd) fails to properly handle DHCP DISCOVER packets with Option 82 in 'forward-only' mode. When Option 82 is present, the relay should drop the packet unless 'trust-option82' is explicitly configured, but instead forwards these packets unmodified to the DHCP server. This allows a malicious or compromised DHCP client in one subnet to request addresses that consume pools belonging to other subnets, causing address pool exhaustion and DoS on the downstream DHCP server.

MitigationConfigure 'trust-option82' appropriately on the DHCP relay interface, or upgrade to the patched versions specified in the Juniper security advisory (JSA/PSN).

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
JunosOperating system
Affected:< 21.2= 21.2= 21.4= 22.2= 22.4= 23.2= 23.4= 24.2= 24.4= 25.2
Junos Os EvolvedOperating system
Affected:< 21.4= 21.4= 22.2= 22.4= 23.2= 23.4= 24.2= 24.4= 25.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Junos version
    Run 'show version' or 'show version detail' on the device CLI
    Affected if The version matches any of these: Junos < 21.2, 21.2, 21.4, 22.2, 22.4, 23.2, 23.4, 24.2, 24.4, or 25.2 (or Junos OS Evolved < 21.4, 21.4, 22.2, 22.4, 23.2, 23.4, 24.2, 24.4, 25.2)
  2. Verify DHCP relay (jdhcpd) is configured
    Run 'show configuration | display set | match relay' to find any DHCP relay configuration
    Affected if DHCP relay is configured on any interface (the vulnerability requires the relay to be active)
  3. Confirm forward-only mode is in use
    Run 'show configuration | display set | match "forward-only"' under the DHCP relay hierarchy
    Affected if Forward-only mode is configured on the DHCP relay interface, which is the vulnerable mode for this issue
  4. Check if trust-option82 is missing
    Run 'show configuration | display set | match "trust-option82"' to see if Option 82 trust is configured
    Affected if Trust-option82 is NOT configured on the relay interface; the vulnerability allows packets to be forwarded when they should be dropped

A device is affected if it runs an affected Junos version, has DHCP relay configured with forward-only mode, and lacks trust-option82 configuration on the interface, allowing untrusted Option 82 packets to bypass filtering and exhaust address pools across subnets.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 21.2 / 21.4 or later
Fixed in 21.221.4
Interim mitigation

Configure 'trust-option82' appropriately on the DHCP relay interface, or upgrade to the patched versions specified in the Juniper security advisory (JSA/PSN).

Recommended fix High confidence

Junos OS: 21.2R3-S10, 21.4R3-S12, 22.4R3-S8, 23.2R2-S5, 23.4R2-S6, 24.2R2-S2, 24.4R2, 25.2R1-S1, or 25.2R2 | Junos OS Evolved: 21.4R3-S12-EVO, 22.4R3-S8-EVO, 23.2R2-S5-EVO, 23.4R2-S6-EVO, 24.2R2-S2-EVO, 24.4R2-EVO, 25.2R1-S1-EVO, or 25.2R2-EVO

  1. 1. Identify the current Junos OS or Junos OS Evolved version running on the device using 'show version'
  2. 2. Determine which branch (21.2, 21.4, 22.2, 22.4, 23.2, 23.4, 24.2, 24.4, or 25.2) the current version belongs to
  3. 3. For Junos OS: upgrade to the first fixed S-release in your branch: 21.2R3-S10, 21.4R3-S12, 22.4R3-S8, 23.2R2-S5, 23.4R2-S6, 24.2R2-S2, 24.4R2, 25.2R1-S1, or 25.2R2
  4. 4. For Junos OS Evolved: upgrade to the first fixed S-release in your branch: 21.4R3-S12-EVO, 22.4R3-S8-EVO, 23.2R2-S5-EVO, 23.4R2-S6-EVO, 24.2R2-S2-EVO, 24.4R2-EVO, 25.2R1-S1-EVO, or 25.2R2-EVO
  5. 5. After upgrade, verify the DHCP relay behavior with Option 82 packets in forward-only mode using packet captures
  6. 6. Alternatively, if immediate upgrade is not possible, configure 'trust-option82' on the DHCP relay interface to explicitly control handling of Option 82 packets (note: this is a mitigation, not a fix for the underlying code bug)
Caveat Upgrading between major releases may introduce behavioral changes; review Junos release notes for DHCP relay changes and test in lab before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,320
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

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Peer-ranked notes from engineers who’ve handled CVE-2025-59960 in production — separate from our analysis above.

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