CVE-2026-57027

Medium

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.

SeverityMedium
CVSS6.5
Exploit probability19. percentile0.3%
ProductJuniper Junos
PublishedJul 9, 2026
First seenJul 9, 2026
Weakness typeCWE-401CWE-401

How to fix

Update
  • juniper junos23.2 or later

Affected products

ProductAffected versionsFixed in
juniper junosv < 23.2, 23.2, 23.4, 24.2, 24.423.2

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