Description
An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of that connection indefinitely in Apache HTTP Server. This could be used to exhaust worker resources in the server, similar to the well known "slow loris" attack pattern. This has been fixed in version 2.4.58, so that such connection are terminated properly after the configured connection timeout. This issue affects Apache HTTP Server: from 2.4.55 through 2.4.57. Users are recommended to upgrade to version 2.4.58, which fixes the issue.
Exploits (1)
References (2)
Core 2
Core References
Third Party Advisory
https://security.netapp.com/advisory/ntap-20231027-0011/
Vendor Advisory vendor-advisory
https://httpd.apache.org/security/vulnerabilities_24.html
Scores
CVSS v3
7.5
EPSS
0.6126
EPSS Percentile
98.3%
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
poc
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-400
Status
published
Products (1)
apache/http_server
2.4.55 - 2.4.58
Published
Oct 23, 2023
Tracked Since
Feb 18, 2026