Resource exhaustion in h2o - CVE-2025-8671
Published: August 13, 2025 / Updated: September 12, 2025
Vulnerability identifier: #VU114025
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/U:Green
CVE-ID: CVE-2025-8671
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vendor: h2o
Affected software:
h2o
h2o
Detailed vulnerability description
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to application does not properly control consumption of internal resources when handling HTTP/2 requests. A remote attacker can send specially crafted HTTP requests to the affected server and consume its all available memory, leading to denial of service.
How to mitigate CVE-2025-8671
Install updates from vendor's website.