Riskcovery

CVE-2026-57027

Junos OS: EX4100 Series, EX4400: With sFlow configured in a VC scenario multicast traffic leads to an FPC crash

State
Published
Severity
7.1 High
Published
Jul 9, 2026
Updated
Jul 10, 2026
Reserved
Jun 23, 2026

Read the record on cve.org

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.

Scores

CVSSScoreVectorSource
4.07.1 HighCVSS: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:Mjuniper
3.16.5 MediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hjuniper

Weaknesses

  • CWE-401 Missing Release of Memory after Effective Lifetime

Affected Products

ProductVersions
Junos OSJuniper Networks
  • before 23.2R2-S7Affected
  • 23.4 to before 23.4R2-S7Affected
  • 24.2 to before 24.2R2-S4Affected
  • 24.4 to before 24.4R2Affected

References

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