Go HTTP/2 SETTINGS Frame DoS Excessive CPU
CVE-2026-78669 Published on October 8, 2026
Excessive CPU consumption from repeated initial window changes in net/http
A malicious HTTP/2 peer can cause excessive CPU consumption in the client or server by opening a large number of streams and then sending many small SETTINGS frames containing SETTINGS_INITIAL_WINDOW_SIZE values.
Vulnerability Analysis
CVE-2026-78669 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is an Amplification Vulnerability?
Software that does not appropriately monitor or control resource consumption can lead to adverse system performance. This situation is amplified if the software allows malicious users or attackers to consume more resources than their access level permits. Exploiting such a weakness can lead to asymmetric resource consumption, aiding in amplification attacks against the system or the network.
CVE-2026-78669 has been classified to as an Amplification vulnerability or weakness.
Products Associated with CVE-2026-78669
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Affected Versions
Go standard library net/http:- Before 1.26.9 is affected.
- Version 1.27.0-0 and below 1.27.2 is affected.
- Before 0.60.0 is affected.