CVE-2026-71418 Suricata doh2: crafted HTTP/2 DATA frames can cause quadratic CPU consumption
Attackers can cause denial of service in Suricata by sending crafted HTTP/2 DATA frames that trigger quadratic CPU consumption during DNS-over-HTTP/2 processing.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-71418?
CVE-2026-71418 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 8.0.0 until 8.0.6, DNS-over-HTTP/2 processing in rust/src/http2/http2.rs retains previously processed HTTP/2 DATA frame contents instead of clearing the internal buffer. Multiple DATA frames with the EndOfStream flag set can grow the buffer to its 65 KiB limit while causing all prior contents to be processed again, producing quadratic CPU complexity, degraded packet processing, loss of monitoring visibility, or denial of service. This issue is fixed in version 8.0.6.
Weakness: CWE-407
Which versions are affected by CVE-2026-71418?
It affects 1 product.
Products include Oisf Suricata.
How do I fix CVE-2026-71418?
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-2026-71418 being exploited?
There is no known exploitation of CVE-2026-71418 in the wild and no public exploit code.
Other vulnerabilities in Oisf Suricata
Sources
Also known as DEBIAN-CVE-2026-71418, GHSA-xjgq-3qw4-jp5f, UBUNTU-CVE-2026-71418.