This security update addresses multiple high-severity vulnerabilities (CVSS scores 7.3-7.5) in the Apache `mod_http2` module, including a use-after-free flaw allowing arbitrary code execution or denial of service (CVE-2026-48913), an HTTP/2 DoS via memory exhaustion (CVE-2025-53020), and a remote DoS via compression bomb and Slowloris-style attacks (CVE-2026-49975). Affected Apache HTTP Server versions are 2.4.17 through 2.4.63 for CVE-2025-53020, and 2.4.55 through 2.4.67 for CVE-2026-48913 and CVE-2026-49975. The vulnerabilities are fixed by upgrading to Apache HTTP Server version 2.4.64 for CVE-2025-53020, and version 2.4.68 for CVE-2026-48913 and CVE-2026-49975.
Red Hat Product Errata RHSA-2026:50572 - Security Advisory Issued: 2026-08-05 Updated: 2026-08-05 RHSA-2026:50572 - Security Advisory Overview Updated Packages Synopsis Important: mod_http2 security update Type/Severity Security Advisory: Important Red Hat Lightspeed patch analysis Identify and remediate systems affected by this advisory. View affected systems Topic An update for mod_http2 is now available for Red Hat Enterprise Linux 9.6 Extended Update Support. 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. Description The mod_h2 Apache httpd module implements the HTTP2 protocol (h2+h2c) on top of libnghttp2 for httpd 2.4 servers. Security Fix(es): mod_http2: Apache HTTP Server: HTTP/2 DoS by Memory Increase (CVE-2025-53020) httpd: httpd: HTTP/2 Remote Denial of Service via compression bomb and Slowloris-style attack (CVE-2026-49975) httpd: mod_http2: Apache HTTP Server mod_http2: Use After Free vulnerability allows arbitrary code execution or denial of service. (CVE-2026-48913) httpd: Apache HTTP Server: Out-of-bounds Read in mod_headers and mod_mime (CVE-2026-43951) 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 Affected Products Red Hat Enterprise Linux for x86_64 - Extended Update Support 9.6 x86_64 Red Hat Enterprise Linux Server - AUS 9.6 x86_64 Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.6 s390x Red Hat Enterprise Linux for Power, little endian - Extended Update Support 9.6 ppc64le Red Hat Enterprise Linux for ARM 64 - Extended Update Support 9.6 aarch64 Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.6 ppc64le Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.6 x86_64 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 9.6 aarch64 Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 9.6 s390x Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.6 x86_64 Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 9.6 aarch64 Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 9.6 ppc64le Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 9.6 s390x Fixes BZ - 2379343 - CVE-2025-53020 mod_http2: Apache HTTP Server: HTTP/2 DoS by Memory Increase BZ - 2485371 - CVE-2026-49975 httpd: httpd: HTTP/2 Remote Denial of Service via compression bomb and Slowloris-style attack BZ - 2486405 - CVE-2026-48913 httpd: mod_http2: Apache HTTP Server mod_http2: Use After Free vulnerability allows arbitrary code execution or denial of service. BZ - 2486415 - CVE-2026-43951 httpd: Apache HTTP Server: Out-of-bounds Read in mod_headers and mod_mime CVEs CVE-2025-53020 CVE-2026-43951 CVE-2026-48913 CVE-2026-49975 References https://access.redhat.com/security/updates/classification/#important Note: More recent versions of these packages may be available. Click a package name for more details. Red Hat Enterprise Linux for x86_64 - Extended Update Support 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 x86_64 mod_http2-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: a7d6eeb2dcbf8b89b81ab62bb20c0389e6df3a2f8ad398dccec899029767efe1 mod_http2-debuginfo-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: b5c463228039686f82bdefb2bf0a5e0c809e1bc7322e42565915d3831c11d04f mod_http2-debugsource-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: a2138f8c144e0d06aababbd6b4697d5892d1a8d9cb97abc2f7e43fb44950f018 Red Hat Enterprise Linux Server - AUS 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 x86_64 mod_http2-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: a7d6eeb2dcbf8b89b81ab62bb20c0389e6df3a2f8ad398dccec899029767efe1 mod_http2-debuginfo-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: b5c463228039686f82bdefb2bf0a5e0c809e1bc7322e42565915d3831c11d04f mod_http2-debugsource-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: a2138f8c144e0d06aababbd6b4697d5892d1a8d9cb97abc2f7e43fb44950f018 Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 s390x mod_http2-2.0.26-4.el9_6.2.s390x.rpm SHA-256: 875f82f41cc4b38f15c1bdd6571eec11fde63d85dc0c3dfc06c1ca4a58a17881 mod_http2-debuginfo-2.0.26-4.el9_6.2.s390x.rpm SHA-256: 95c4fd02add58043528c37f886b0be942e6f671c685a113f46ac8d0087d5942d mod_http2-debugsource-2.0.26-4.el9_6.2.s390x.rpm SHA-256: 2cea2a2bc60d8c87eaa68d48d20d9dae91f54cfa9f9e45ef7982f812c1ae6ac6 Red Hat Enterprise Linux for Power, little endian - Extended Update Support 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 ppc64le mod_http2-2.0.26-4.el9_6.2.ppc64le.rpm SHA-256: efef9762b721e5a6dd234d225cf4e8d2cd8e6d3bd7d57f6e2b314092787698b0 mod_http2-debuginfo-2.0.26-4.el9_6.2.ppc64le.rpm SHA-256: 14b6f3fed92787673f8ba7929b28b2832ea231d26b51965c76c4daa654ddae07 mod_http2-debugsource-2.0.26-4.el9_6.2.ppc64le.rpm SHA-256: 1d526776bddf0dc2532572fd77b52c58d79ffab05552c94b576f4b182cdd5da0 Red Hat Enterprise Linux for ARM 64 - Extended Update Support 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 aarch64 mod_http2-2.0.26-4.el9_6.2.aarch64.rpm SHA-256: 0b3dc1caaa661e3d50c01d5037def3191b77335d800a9d942a261502f3f957cb mod_http2-debuginfo-2.0.26-4.el9_6.2.aarch64.rpm SHA-256: 7ea7732e985b6ff899542f05fb07bce0862aa8d3ac17b0897a417101ad95c419 mod_http2-debugsource-2.0.26-4.el9_6.2.aarch64.rpm SHA-256: f0f3b293b4eeef63df2a30956d9b6daeb3142987c7aa5f424f7eccb387865310 Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 ppc64le mod_http2-2.0.26-4.el9_6.2.ppc64le.rpm SHA-256: efef9762b721e5a6dd234d225cf4e8d2cd8e6d3bd7d57f6e2b314092787698b0 mod_http2-debuginfo-2.0.26-4.el9_6.2.ppc64le.rpm SHA-256: 14b6f3fed92787673f8ba7929b28b2832ea231d26b51965c76c4daa654ddae07 mod_http2-debugsource-2.0.26-4.el9_6.2.ppc64le.rpm SHA-256: 1d526776bddf0dc2532572fd77b52c58d79ffab05552c94b576f4b182cdd5da0 Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 x86_64 mod_http2-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: a7d6eeb2dcbf8b89b81ab62bb20c0389e6df3a2f8ad398dccec899029767efe1 mod_http2-debuginfo-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: b5c463228039686f82bdefb2bf0a5e0c809e1bc7322e42565915d3831c11d04f mod_http2-debugsource-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: a2138f8c144e0d06aababbd6b4697d5892d1a8d9cb97abc2f7e43fb44950f018 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 aarch64 mod_http2-2.0.26-4.el9_6.2.aarch64.rpm SHA-256: 0b3dc1caaa661e3d50c01d5037def3191b77335d800a9d942a261502f3f957cb mod_http2-debuginfo-2.0.26-4.el9_6.2.aarch64.rpm SHA-256: 7ea7732e985b6ff899542f05fb07bce0862aa8d3ac17b0897a417101ad95c419 mod_http2-debugsource-2.0.26-4.el9_6.2.aarch64.rpm SHA-256: f0f3b293b4eeef63df2a30956d9b6daeb3142987c7aa5f424f7eccb387865310 Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 s390x mod_http2-2.0.26-4.el9_6.2.s390x.rpm SHA-256: 875f82f41cc4b38f15c1bdd6571eec11fde63d85dc0c3dfc06c1ca4a58a17881 mod_http2-debuginfo-2.0.26-4.el9_6.2.s390x.rpm SHA-256: 95c4fd02add58043528c37f886b0be942e6f671c685a113f46ac8d0087d5942d mod_http2-debugsource-2.0.26-4.el9_6.2.s390x.rpm SHA-256: 2cea2a2bc60d8c87eaa68d48d20d9dae91f54cfa9f9e45ef7982f812c1ae6ac6 Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 x86_64 mod_http2-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: a7d6eeb2dcbf8b89b81ab62bb20c0389e6df3a2f8ad398dccec899029767efe1 mod_http2-debuginfo-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: b5c463228039686f82bdefb2bf0a5e0c809e1bc7322e42565915d3831c11d04f mod_http2-debugsource-2.0.26-4.el9_6.2.x86_64.rpm SHA-256: a2138f8c144e0d06aababbd6b4697d5892d1a8d9cb97abc2f7e43fb44950f018 Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 aarch64 mod_http2-2.0.26-4.el9_6.2.aarch64.rpm SHA-256: 0b3dc1caaa661e3d50c01d5037def3191b77335d800a9d942a261502f3f957cb mod_http2-debuginfo-2.0.26-4.el9_6.2.aarch64.rpm SHA-256: 7ea7732e985b6ff899542f05fb07bce0862aa8d3ac17b0897a417101ad95c419 mod_http2-debugsource-2.0.26-4.el9_6.2.aarch64.rpm SHA-256: f0f3b293b4eeef63df2a30956d9b6daeb3142987c7aa5f424f7eccb387865310 Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 9.6 SRPM mod_http2-2.0.26-4.el9_6.2.src.rpm SHA-256: 10c535e8bbab47fc1a2a2e179ff8ac59def154e69170f4a206d42314922ea977 ppc64le mod_http2-2.0.26-4.el9_6.2.ppc64le.rpm SHA-256: efef9762b721e5a6dd234d225cf4e8d2cd8e6d3bd7d57f6e2b314092787698b0 mod_http2-debuginfo-2.0.26-4.el9_6.2.ppc64le.rpm SHA-256: 14b6f3fed92787673f8ba7929b28b2832ea231d26b51965c76c4daa654ddae07 mod_http2-debugsource-2.0.26-4.el9_6.2.ppc64le.rpm SHA-256: 1d526776bddf0dc2532572fd77b52c58d79ffab05552c94b576f4b182cdd5da0 Red Hat Enterprise Linux for IBM