Description
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".
References (4)
Scores
CVSS v3
7.5
EPSS
0.0101
EPSS Percentile
77.2%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-617
Status
published
Products (1)
apache/http_server
2.4.26 - 2.4.64
Published
Jul 10, 2025
Tracked Since
Feb 18, 2026