Resource Exhaustion Affecting mod_http2 package, versions <0:2.0.26-1.el9


Severity

Recommended
medium

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
70.6% (100th percentile)

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  • Snyk IDSNYK-ALMALINUX9-MODHTTP2-6811260
  • published7 May 2024
  • disclosed30 Apr 2024

Introduced: 30 Apr 2024

CVE-2023-43622  (opens in a new tab)
CWE-400  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:9 mod_http2 to version 0:2.0.26-1.el9 or higher.
This issue was patched in ALSA-2024:2368.

NVD Description

Note: Versions mentioned in the description apply only to the upstream mod_http2 package and not the mod_http2 package as distributed by AlmaLinux. See How to fix? for AlmaLinux:9 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1