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Medium severity6.5NVD Advisory· Published Apr 9, 2026· Updated Apr 17, 2026

CVE-2026-33781

CVE-2026-33781

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.

Affected products

8
  • Juniper Networks/Junos8 versions
    cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:*+ 7 more
    • cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:*
    • cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:*
    • cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:*
    • cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:*
    • cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:*
    • cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:*
    • cpe:2.3:o:juniper:junos:25.2:r2:*:*:*:*:*:*
    • (no CPE)range: >=24.4R1, <24.4R2; >=25.2R1, <25.2R1-S1 or <25.2R2

Patches

Vulnerability mechanics

References

1

News mentions

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