Apache HTTP Server protocol handler for the HTTP/2 protocol checks received request headers against the size limitations as configured for the server...
Summary
NULL pointer dereference on specially crafted HTTP/2 request
Original description
The description as published by the source.
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.
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Alpine Linux ALPINE-CVE-2021-31618 apache2 Fixed in: 2.4.48-r0
- Debian DEBIAN-CVE-2021-31618 apache2 Fixed in: 2.4.46-5
References
- advisory httpd.apache.org
- advisory openwall.com
- advisory lists.debian.org
- advisory seclists.org
- advisory security.gentoo.org
- advisory security.netapp.com
- advisory debian.org
- patch oracle.com
- web lists.apache.org
- web lists.apache.org
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web openwall.com
- web nvd.nist.gov