Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
None
Attack Vector
Network
0

CVE-2021-31618

Disclosure Date: June 15, 2021
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

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.

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CVSS V3 Severity and Metrics
Base Score:
7.5 High
Impact Score:
3.6
Exploitability Score:
3.9
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
None
Availability (A):
High

General Information

Vendors

  • apache,
  • debian,
  • fedoraproject,
  • oracle

Products

  • debian linux 10.0,
  • debian linux 9.0,
  • enterprise manager ops center 12.4.0.0,
  • fedora 33,
  • fedora 34,
  • http server 1.15.17,
  • http server 2.4.47,
  • instantis enterprisetrack 17.1,
  • instantis enterprisetrack 17.2,
  • instantis enterprisetrack 17.3,
  • zfs storage appliance kit 8.8

References

Additional Info

Technical Analysis