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MEDIUM · 6.5

CVE-2026-57027

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 a...

Vulnerability Description

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. The leak can be monitored by watching the continuous increase of the buffer values in the output of: user@host> show chassis fpc This issue affects Junos OS on EX4100 Series and EX4400: * all versions before 23.2R2-S7, * 23.4 versions before 23.4R2-S7, * 24.2 versions before 24.2R2-S4, * 24.4 versions before 24.4R2.

CVSS Score

6.5

MEDIUM

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH

Affected Products

VendorProductVersions
JuniperJunos< 23.2
JuniperEx4100-
JuniperEx4100-F-
JuniperEx4100-H-
JuniperEx4100-H-12T-
JuniperEx4400-

Related Weaknesses (CWE)

CWE-401

References

FAQ

What is CVE-2026-57027?

CVE-2026-57027 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 a...

How severe is CVE-2026-57027?

CVE-2026-57027 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-57027?

Check the references section above for vendor advisories and patch information. Affected products include: Juniper Junos, Juniper Ex4100, Juniper Ex4100-F, Juniper Ex4100-H, Juniper Ex4100-H-12T.