Junos OS (SRX firewalls)
CVE-2026-33782: MX Series: In specific DHCPv6 scenarios jdhcpd memory increases continuously with subscriber logouts
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).
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Junos OS (MX Series) 0 | 22.4R3-S1 or later |
| Junos OS (MX Series) 23.2 | 23.2R2 or later |
| Junos OS (MX Series) 23.4 | 23.4R2 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Workarounds
There are no known workarounds for this issue.
Exploitation
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.