CVE-2023-36835 Denial of service in Junos OS
A network-based attacker can cause a persistent denial of service on Juniper QFX10000 switches by sending a specific IP packet routed over VXLAN.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2023-36835?
CVE-2023-36835 is a high-severity denial of service vulnerability in Juniper Junos, published on 14 Jul 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-754
Which versions are affected by CVE-2023-36835?
It affects 1 product.
Products include Juniper Junos.
How do I fix CVE-2023-36835?
No fix has been published for CVE-2023-36835 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-36835 being exploited?
There is no known exploitation of CVE-2023-36835 in the wild and no public exploit code.
Other vulnerabilities in Juniper Junos
- CVE-2023-36845 Juniper Junos OS EX Series and SRX Series PHP External Variable Modification
- CVE-2020-1631 Juniper Junos OS Path Traversal
- CVE-2025-21590 Juniper Junos OS Improper Isolation or Compartmentalization
- CVE-2023-36851 Juniper Junos OS SRX Series Missing Authentication for Critical Function
- CVE-2023-36844 Juniper Junos OS EX Series PHP External Variable Modification
Sources
Also known as GHSA-3xwf-x58p-42cm.