CVE-2021-31618

Advisory lineage Upstream: 0 Downstream: 10
Modified
Published: 15 Jun 2021, 00:00
Last modified:03 Aug 2024, 23:03

Vulnerability Summary

Overall Risk (default)
medium
32/100
CVSS Score
7.5 HIGH
v3.1 (nvd)
EPSS Score
11% MEDIUM
11% probability -7.52%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

15 Jun 2021, 00:00
Published
Vulnerability first disclosed
03 Aug 2024, 23:03
Last Modified
Vulnerability information updated

Description

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.

CVSS Metrics

  • v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  • v2.0•MEDIUM•Score: 5AV:N/AC:L/Au:N/C:N/I:N/A:P

EPSS Trends

Current EPSS score: 11.00%• Percentile: 94%

Techniques & Countermeasures

  • CWE-476•NULL Pointer Dereference

    The product dereferences a pointer that it expects to be valid but is NULL.

Affected Systems

  • apache software foundation•apache http server

    2.4.47

  • Unknown•HTTP Server

    1.15.17 | 2.4.47

  • debian•debian_linux

    9.0 | 10.0

  • fedoraproject•fedora

    33 | 34

  • oracle•enterprise_manager_ops_center

    12.4.0.0

  • oracle•instantis_enterprisetrack

    17.1 | 17.2 | 17.3

  • oracle•zfs_storage_appliance_kit

    8.8

References (13)