CVE-2025-21591

Summary

A Buffer Access with Incorrect Length Value vulnerability in the jdhcpd daemon of Juniper Networks Junos OS, when DHCP snooping is enabled, allows an unauthenticated, adjacent, attacker to send a DHCP packet with a malformed DHCP option to cause jdhcp to crash creating a Denial of Service (DoS) condition.

Continuous receipt of these DHCP packets using the malformed DHCP Option will create a sustained Denial of Service (DoS) condition.

This issue affects Junos OS:

  • from 23.1 before 23.2R2-S3,
  • from 23.4 before 23.4R2-S3,
  • from 24.2 before 24.2R2.

This issue isn't applicable to any versions of Junos OS before 23.1R1.

This issue doesn't affect vSRX Series which doesn't support DHCP Snooping.

This issue doesn't affect Junos OS Evolved.

There are no indicators of compromise for this issue.

Affected Software

VendorProductVersion RangeStatus
Juniper NetworksJunos OS23.1 < 23.2R2-S3affected
Juniper NetworksJunos OS23.4 < 23.4R2-S3affected
Juniper NetworksJunos OS24.2 < 24.2R2affected
Juniper NetworksJunos OS0 <= 23.1R1unaffected

Weaknesses

  • CWE-805: CWE-805: Buffer Access with Incorrect Length Value

Workarounds

There are no known workarounds for this issue.

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References