Apache HTTP Server 2.4.x: mod_proxy_http2 assertion triggers DoS via proxy
CVE-2025-49630 Published on July 10, 2025
Apache HTTP Server: mod_proxy_http2 denial of service
In certain proxy configurations, a denial of service attack against Apache HTTP Server versions 2.4.26 through to 2.4.63 can be triggered by untrusted clients causing an assertion in mod_proxy_http2.
Configurations affected are a reverse proxy is configured for an HTTP/2 backend, with ProxyPreserveHost set to "on".
Vulnerability Analysis
CVE-2025-49630 is exploitable 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.
Timeline
Report received
Weakness Type
What is an assertion failure Vulnerability?
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
CVE-2025-49630 has been classified to as an assertion failure vulnerability or weakness.
Products Associated with CVE-2025-49630
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Affected Versions
Apache Software Foundation Apache HTTP Server:- Version 2.4.26, <= 2.4.63 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.