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CVE-2026-33782: Junos OS: MX Series: In specific DHCPv6 scenarios jdhcpd memory increases continuously with subscriber logouts
- Severity: medium (CVSS 6.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-04-09 · updated 2026-10-26
- Weakness: CWE-401
Description
A Missing Release of Memory after Effective Lifetime vulnerability in the DHCP daemon (jdhcpd) of Juniper Networks Junos OS on MX Series, allows an adjacent, unauthenticated attacker to cause a memory leak, that will eventually cause a complete Denial-of-Service (DoS). In a DHCPv6 over PPPoE, or DHCPv6 over VLAN with Active lease query or Bulk lease query scenario, every subscriber logout will leak a small amount of memory. When all available memory has been exhausted, jdhcpd will crash and restart which causes a complete service impact until the process has recovered. The memory usage of jdhcpd can be monitored with: user@host> show system processes extensive | match jdhcpd This issue affects Junos OS: * all versions before 22.4R3-S1, * 23.2 versions before 23.2R2, * 23.4 versions before 23.4R2.
Affected products
- Juniper Junos OS: before 22.4; 22.4, 22.4-r1, 22.4-r1-s1, 22.4-r1-s2, 22.4-r2, 22.4-r2-s1 (+10) — fixed in 22.4
How to fix
Upgrade to a fixed version: Juniper Junos OS 22.4. Check the vendor advisory for mitigations.
References
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