CVSS: v3.1: 6.5 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)CVSS: v4.0: 7.1 (CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:M)
A Missing Release of Memory after Effective Lifetime vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on specific EX Series devices allows an unauthenticated adjacent attacker to cause a Denial-of-Service (DoS).
When sFlow is configured in a Virtual Chassis (VC) scenario with EX4100 Series or EX4400 Series devices, multicast traffic which is received on one VC member and sent out on another member leads to a memory leak and ultimately an FPC crash and restart.
This issue affects Junos OS on EX4100 Series and EX4400:
A system is only affected if sFlow for multicast is explicitly enabled with:[ forwarding-options sflow egress-multicast enable ]
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
This issue was seen during production usage.
This issue has been assigned CVE-2026-57027.
The following software releases have been updated to resolve this specific issue: Junos OS: 23.2R2-S7, 23.4R2-S7, 24.2R2-S4, 24.4R2, 25.2R1, and all subsequent releases.
This issue is being tracked as 1824592 which is visible on the Customer Support website.
Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).
There are no known workarounds for this issue.
2026-07-08: Initial Publication