# CVE-2023-43622: apache2: An attacker, opening a HTTP/2 connection with an initial window size of 0, was able to block handling of that connect... CVE-2023-43622 is fixed in 22 products on 1 platform, first by DEBIAN-CVE-2023-43622, released October 23, 2023. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2023-43622 - Priority: High - CVSS: 7.5 (high) - EPSS: 0.6882 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Oct 23, 2023 ## 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. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | apache2 Debian 12.15 (bookworm) | 2.4.59-1~deb12u1 | [DEBIAN-CVE-2023-43622](https://patchblox.com/security/data/fix/linux/debian-cve-2023-43622.md) | Oct 23, 2023 | | Linux | apache2 Debian 13.5 (trixie) | 2.4.58-1 | [DEBIAN-CVE-2023-43622](https://patchblox.com/security/data/fix/linux/debian-cve-2023-43622.md) | Oct 23, 2023 | | Linux | apache2 Debian 14 | 2.4.58-1 | [DEBIAN-CVE-2023-43622](https://patchblox.com/security/data/fix/linux/debian-cve-2023-43622.md) | Oct 23, 2023 | | Linux | httpd amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | httpd-core amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | httpd-core-debuginfo amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | httpd-debuginfo amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | httpd-debugsource amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | httpd-devel amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | httpd-filesystem amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | httpd-manual amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | httpd-tools amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | httpd-tools-debuginfo amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | mod_http2 RHEL 9 | 0:2.0.26-1.el9 | [RHSA-2024:2368](https://patchblox.com/security/data/fix/linux/rhsa-2024-2368.md) | Apr 30, 2024 | | Linux | mod_http2 almalinux 9 | 2.0.26-1.el9 | [ALSA-2024:2368](https://patchblox.com/security/data/fix/linux/alsa-2024-2368.md) | Apr 30, 2024 | | Linux | mod_http2 ol 9 | 0:2.0.26-1.el9 | [ELSA-2024-2368](https://patchblox.com/security/data/fix/linux/elsa-2024-2368.md) | May 2, 2024 | | Linux | mod_ldap amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | mod_ldap-debuginfo amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | mod_lua amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | mod_lua-debuginfo amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | mod_proxy_html amzn 2023 | 1:2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | mod_proxy_html-debuginfo amzn 2023 | 1:2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | mod_session amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | mod_session-debuginfo amzn 2023 | 2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | mod_ssl amzn 2023 | 1:2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | | Linux | mod_ssl-debuginfo amzn 2023 | 1:2.4.58-1.amzn2023 | [ALAS2023-2023-433](https://patchblox.com/security/data/fix/linux/alas2023-2023-433.md) | Nov 9, 2023 | --- Data as of 2026-11-08T13:06:02Z UTC. 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