CVE-2023-43622

High

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.

SeverityHigh

CVSS7.5

Exploit probability—

Product

Apache Http Server

PublishedOct 23, 2023

First seenOct 23, 2023

Weakness typeCWE-400Uncontrolled resource consumption

How to fix

Update

apache http_server2.4.58 or later

Vendor advisories

httpd.apache.org/security/vulnerabilities_24.html

Affected products

Product	Affected versions	Fixed in
apache http_server	2.4.55 ≤ v < 2.4.58	2.4.58

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