CVE-2026-63447 Suricata ftp: crafted FTP traffic can cause quadratic CPU consumption
Crafted FTP traffic causes quadratic CPU consumption in Suricata, leading to denial of service and reduced monitoring visibility.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-63447?
CVE-2026-63447 is a high-severity denial of service vulnerability in Oisf Suricata, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. From 8.0.5 until 8.0.6, the FTP parser in src/app-layer-ftp.c can continue allocating transactions after app-layer.protocols.ftp.max-tx is reached while processing one large chunk of FTP command data. The oversized transaction list is repeatedly processed with quadratic complexity after the too_many_transactions event, allowing crafted FTP traffic to degrade packet processing, reduce monitoring visibility, or cause denial of service. This issue is fixed in version 8.0.6.
Weakness: CWE-407
Which versions are affected by CVE-2026-63447?
It affects 1 product.
Products include Oisf Suricata.
How do I fix CVE-2026-63447?
Upgrade to a fixed version.
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-2026-63447 being exploited?
There is no known exploitation of CVE-2026-63447 in the wild and no public exploit code.
Other vulnerabilities in Oisf Suricata
Sources
Also known as DEBIAN-CVE-2026-63447, GHSA-w394-3g33-3jg9, UBUNTU-CVE-2026-63447.