CVE-2024-21606 Junos OS: SRX Series: When "tcp-encap" is configured and specific packets are received flowd will crash
An unauthenticated attacker can cause a denial of service on Juniper SRX devices by sending specific packets when tcp-encap is configured.
- 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-2024-21606?
CVE-2024-21606 is a high-severity use after free vulnerability in Juniper Junos, published on 12 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX Series allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS).
In a remote access VPN scenario, if a "tcp-encap-profile" is configured and a sequence of specific packets is received, a flowd crash and restart will be observed.
This issue affects Juniper Networks Junos OS on SRX Series:
* All versions earlier than 20.4R3-S8; * 21.2 versions earlier than 21.2R3-S6; * 21.3 versions earlier than 21.3R3-S5; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3-S3; * 22.2 versions earlier than 22.2R3-S3; * 22.3 versions earlier than 22.3R3-S1; * 22.4 versions earlier than 22.4R2-S2, 22.4R3.
Weakness: CWE-415
Which versions are affected by CVE-2024-21606?
It affects 1 product.
Products include Juniper Junos.
How do I fix CVE-2024-21606?
No fix has been published for CVE-2024-21606 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2024-21606 being exploited?
There is no known exploitation of CVE-2024-21606 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-ww73-qp64-xm6q.