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Fencer Vulns
high 7.5

CVE-2023-36835 json

Junos OS: QFX10000 Series: All traffic will be dropped after a specific valid IP packet has been received which needs to be routed over a VXLAN tunnel

published 2023-07-14 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-40755

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 51%
public exploits
0
none known

Summary

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on QFX10000 Series allows a network based attacker to cause a Denial of Service (DoS).

If a specific valid IP packet is received and that packet needs to be routed over a VXLAN tunnel, this will result in a PFE wedge condition due to which traffic gets impacted. As this is not a crash and restart scenario, this condition will persist until the system is rebooted to recover.

This issue affects Juniper Networks Junos OS on QFX10000: 20.3 version 20.3R1 and later versions; 20.4 versions prior to 20.4R3-S5; 21.1 versions prior to 21.1R3-S5; 21.2 versions prior to 21.2R3-S5; 21.3 versions prior to 21.3R3-S4; 21.4 versions prior to 21.4R3-S1; 22.1 versions prior to 22.1R3; 22.2 versions prior to 22.2R2; 22.3 versions prior to 22.3R1-S2, 22.3R2.

Patch / fix

  • Juniper Networks Junos OS 20.4R3-S5, 21.1R3-S5, 21.2R3-S5, 21.3R3-S4, 21.4R3-S1, 22.1R3, 22.2R2, 22.3R1-S2, 22.3R2
  • juniper_networks junos_os 20.4R3-S5, 21.1R3-S5, 21.2R3-S5, 21.3R3-S4, 21.4R3-S1, 22.1R3, 22.2R2, 22.3R1-S2, 22.3R2

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.64% chance of exploitation in the next 30 days, higher than 51% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Juniper Networks Junos OS
  • juniper_networks junos_os

Classification

Weakness
  • CWE-754 Improper Check for Unusual or Exceptional Conditions

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.