{"id":"ALPINE-CVE-2021-31618","details":"Apache HTTP Server protocol handler for the HTTP/2 protocol checks received request headers against the size limitations as configured for the server and used for the HTTP/1 protocol as well. On violation of these restrictions and HTTP response is sent to the client with a status code indicating why the request was rejected. This rejection response was not fully initialised in the HTTP/2 protocol handler if the offending header was the very first one received or appeared in a a footer. This led to a NULL pointer dereference on initialised memory, crashing reliably the child process. Since such a triggering HTTP/2 request is easy to craft and submit, this can be exploited to DoS the server. This issue affected mod_http2 1.15.17 and Apache HTTP Server version 2.4.47 only. Apache HTTP Server 2.4.47 was never released.","modified":"2026-08-27T22:18:01.609581733Z","published":"2021-06-15T09:15:07.960Z","upstream":["CVE-2021-31618"],"references":[{"type":"ADVISORY","url":"https://security.alpinelinux.org/vuln/CVE-2021-31618"}],"affected":[{"package":{"name":"apache2","ecosystem":"Alpine:v3.10","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.11","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.12","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.13","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.14","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.15","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.16","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.17","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.18","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.19","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.20","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.21","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.22","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.23","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecosystem_specific":{},"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/alpine/ALPINE-CVE-2021-31618.json"}},{"package":{"name":"apache2","ecosystem":"Alpine:v3.24","purl":"pkg:apk/alpine/apache2?arch=source"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.48-r0"}]}],"ecos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