CVE-2021-31618 NULL pointer dereference on specially crafted HTTP/2 request

2021-06-1500:00:00

CWE-476

apache

github.com

6.8 Medium

AI Score

Confidence

Low

0.019 Low

EPSS

Percentile

88.7%

JSON

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.

CNA Affected

[
  {
    "vendor": "Apache Software Foundation",
    "product": "Apache HTTP Server",
    "versions": [
      {
        "version": "2.4.47",
        "status": "affected"
      }
    ]
  }
]