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CVE-2026-33781

HIGH CVSS 4.0: 7.1 EPSS 0.02%
Updated Apr 17, 2026
Juniper
Parameter Value
CVSS 7.1 (HIGH)
Type CWE-754
Vendor Juniper
Public PoC No

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.

Attack Parameters

Attack Vector
Adjacent
Requires local network access
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v4.0

Weakness Type (CWE)

Vulnerable Products 25

Configuration From (including) Up to (excluding)
Juniper Junos
cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:*
Juniper Junos
cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:*
Juniper Junos
cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:*
Juniper Junos
cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:*
Juniper Junos
cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:*
Juniper Junos
cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:*
Juniper Junos
cpe:2.3:o:juniper:junos:25.2:r2:*:*:*:*:*:*
Juniper Ex4000
cpe:2.3:h:juniper:ex4000:-:*:*:*:*:*:*:*
Juniper Ex4100
cpe:2.3:h:juniper:ex4100:-:*:*:*:*:*:*:*
Juniper Ex4100-F
cpe:2.3:h:juniper:ex4100-f:-:*:*:*:*:*:*:*
Juniper Ex4100-H
cpe:2.3:h:juniper:ex4100-h:-:*:*:*:*:*:*:*
Juniper Ex4300
cpe:2.3:h:juniper:ex4300:-:*:*:*:*:*:*:*
Juniper Ex4400
cpe:2.3:h:juniper:ex4400:-:*:*:*:*:*:*:*
Juniper Ex4600
cpe:2.3:h:juniper:ex4600:-:*:*:*:*:*:*:*
Juniper Ex4650
cpe:2.3:h:juniper:ex4650:-:*:*:*:*:*:*:*
Juniper Qfx5110
cpe:2.3:h:juniper:qfx5110:-:*:*:*:*:*:*:*
Juniper Qfx5120
cpe:2.3:h:juniper:qfx5120:-:*:*:*:*:*:*:*
Juniper Qfx5130
cpe:2.3:h:juniper:qfx5130:-:*:*:*:*:*:*:*
Juniper Qfx5200
cpe:2.3:h:juniper:qfx5200:-:*:*:*:*:*:*:*
Juniper Qfx5210
cpe:2.3:h:juniper:qfx5210:-:*:*:*:*:*:*:*
Juniper Qfx5220
cpe:2.3:h:juniper:qfx5220:-:*:*:*:*:*:*:*
Juniper Qfx5230-64cd
cpe:2.3:h:juniper:qfx5230-64cd:-:*:*:*:*:*:*:*
Juniper Qfx5240
cpe:2.3:h:juniper:qfx5240:-:*:*:*:*:*:*:*
Juniper Qfx5241
cpe:2.3:h:juniper:qfx5241:-:*:*:*:*:*:*:*
Juniper Qfx5700
cpe:2.3:h:juniper:qfx5700:-:*:*:*:*:*:*:*