VAR-201908-0260

Vulnerability from variot - Updated: 2025-12-22 21:59

Some HTTP/2 implementations are vulnerable to unconstrained interal data buffering, potentially leading to a denial of service. The attacker opens the HTTP/2 window so the peer can send without constraint; however, they leave the TCP window closed so the peer cannot actually write (many of) the bytes on the wire. The attacker then sends a stream of requests for a large response object. Depending on how the servers queue the responses, this can consume excess memory, CPU, or both. Multiple HTTP/2 implementations are vulnerable to a variety of denial-of-service (DoS) attacks. HTTP/2 is the second version of the hypertext transfer protocol, which is mainly used to ensure the communication between the client and the server. A resource management error vulnerability exists in HTTP/2. Solution:

Before applying this update, make sure all previously released errata relevant to your system have been applied.

This release serves as a replacement for Red Hat JBoss Core Services Pack Apache Server 2.4.29 and includes bug fixes and enhancements. Refer to the Release Notes for information on the most significant bug fixes and enhancements included in this release. -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256

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Red Hat Security Advisory

Synopsis: Important: httpd24-httpd and httpd24-nghttp2 security update Advisory ID: RHSA-2019:2949-01 Product: Red Hat Software Collections Advisory URL: https://access.redhat.com/errata/RHSA-2019:2949 Issue date: 2019-10-01 CVE Names: CVE-2019-9511 CVE-2019-9513 CVE-2019-9517 ==================================================================== 1. Summary:

An update for httpd24-httpd and httpd24-nghttp2 is now available for Red Hat Software Collections.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Relevant releases/architectures:

Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) - noarch, x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) - aarch64, noarch, ppc64le, s390x, x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.5) - noarch, ppc64le, s390x, x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.6) - noarch, ppc64le, s390x, x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7) - noarch, ppc64le, s390x, x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) - noarch, x86_64 Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) - noarch, x86_64

Description:

The httpd packages provide the Apache HTTP Server, a powerful, efficient, and extensible web server.

Security Fix(es):

HTTP/2: large amount of data requests leads to denial of service (CVE-2019-9511)
HTTP/2: flood using PRIORITY frames resulting in excessive resource consumption (CVE-2019-9513)
HTTP/2: request for large response leads to denial of service (CVE-2019-9517)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Solution:

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

After installing the updated packages, the httpd daemon will be restarted automatically.

Bugs fixed (https://bugzilla.redhat.com/):

1735741 - CVE-2019-9513 HTTP/2: flood using PRIORITY frames results in excessive resource consumption 1741860 - CVE-2019-9511 HTTP/2: large amount of data requests leads to denial of service 1741868 - CVE-2019-9517 HTTP/2: request for large response leads to denial of service

Package List:

Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6):

Source: httpd24-httpd-2.4.34-8.el6.1.src.rpm httpd24-nghttp2-1.7.1-7.el6.1.src.rpm

noarch: httpd24-httpd-manual-2.4.34-8.el6.1.noarch.rpm

x86_64: httpd24-httpd-2.4.34-8.el6.1.x86_64.rpm httpd24-httpd-debuginfo-2.4.34-8.el6.1.x86_64.rpm httpd24-httpd-devel-2.4.34-8.el6.1.x86_64.rpm httpd24-httpd-tools-2.4.34-8.el6.1.x86_64.rpm httpd24-libnghttp2-1.7.1-7.el6.1.x86_64.rpm httpd24-libnghttp2-devel-1.7.1-7.el6.1.x86_64.rpm httpd24-mod_ldap-2.4.34-8.el6.1.x86_64.rpm httpd24-mod_proxy_html-2.4.34-8.el6.1.x86_64.rpm httpd24-mod_session-2.4.34-8.el6.1.x86_64.rpm httpd24-mod_ssl-2.4.34-8.el6.1.x86_64.rpm httpd24-nghttp2-1.7.1-7.el6.1.x86_64.rpm httpd24-nghttp2-debuginfo-1.7.1-7.el6.1.x86_64.rpm

Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6):

Source: httpd24-httpd-2.4.34-8.el6.1.src.rpm httpd24-nghttp2-1.7.1-7.el6.1.src.rpm

noarch: httpd24-httpd-manual-2.4.34-8.el6.1.noarch.rpm

Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7):