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MEDIUM · 6.5

CVE-2026-33781

An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on specific EX and QFX Series devices allow an unauthenticated,...

Vulnerability Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on specific EX and QFX Series devices allow an unauthenticated, adjacent attacker to cause a complete Denial of Service (DoS). On EX4k, and QFX5k platforms configured as service-provider edge devices, if L2PT is enabled on the UNI and VSTP is enabled on NNI in VXLAN scenarios, receiving VSTP BPDUs on UNI leads to packet buffer allocation failures, resulting in the device to not pass traffic anymore until it is manually recovered with a restart.This issue affects Junos OS: * 24.4 releases before 24.4R2, * 25.2 releases before 25.2R1-S1, 25.2R2. This issue does not affect Junos OS releases before 24.4R1.

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
JuniperJunos24.4
JuniperEx4000-
JuniperEx4100-
JuniperEx4100-F-
JuniperEx4100-H-
JuniperEx4300-
JuniperEx4400-
JuniperEx4600-
JuniperEx4650-
JuniperQfx5110-
JuniperQfx5120-
JuniperQfx5130-
JuniperQfx5200-
JuniperQfx5210-
JuniperQfx5220-
JuniperQfx5230-64Cd-
JuniperQfx5240-
JuniperQfx5241-
JuniperQfx5700-

Related Weaknesses (CWE)

CWE-754

References

FAQ

What is CVE-2026-33781?

CVE-2026-33781 is a vulnerability with a CVSS score of 6.5 (MEDIUM). An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on specific EX and QFX Series devices allow an unauthenticated,...

How severe is CVE-2026-33781?

CVE-2026-33781 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-2026-33781?

Check the references section above for vendor advisories and patch information. Affected products include: Juniper Junos, Juniper Ex4000, Juniper Ex4100, Juniper Ex4100-F, Juniper Ex4100-H.