CVE-2024-39540 Junos OS: SRX Series, and MX Series with SPC3: Specific valid TCP traffic can cause a pfe crash
An unauthenticated attacker can cause a Packet Forwarding Engine crash and service outage on Juniper SRX and MX devices by sending specific valid TCP traffic.
- 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-2024-39540?
CVE-2024-39540 is a high-severity denial of service vulnerability in Juniper Junos, published on 11 Jul 2024. 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 SRX Series, and MX Series with SPC3 allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).
When an affected device receives specific valid TCP traffic, the pfe crashes and restarts leading to a momentary but complete service outage.
This issue affects Junos OS:
21.2 releases from 21.2R3-S5 before 21.2R3-S6.
This issue does not affect earlier or later releases.
Weakness: CWE-754
Which versions are affected by CVE-2024-39540?
It affects 1 product.
Products include Juniper Junos.
How do I fix CVE-2024-39540?
No fix has been published for CVE-2024-39540 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-2024-39540 being exploited?
There is no known exploitation of CVE-2024-39540 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-xwcp-g9fq-2mmp.