DEBIAN-CVE-2021-31618

Advisory lineage Upstream: 1 Downstream: 2
Upstream
CVE-2021-31618
Published: 15 Jun 2021, 09:15
Last modified:28 Apr 2026, 20:22

Vulnerability Summary

Overall Risk (default)
medium
30/100
CVSS Score
7.5 HIGH
3.1 (osv_debian)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

15 Jun 2021, 09:15
Published
Vulnerability first disclosed
28 Apr 2026, 20:22
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

Affected Systems

  • debian•apache2

    < 2.4.46-5 | < 2.4.46-5 | < 2.4.46-5 | < 2.4.46-5

References (1)