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CVE-2021-31618

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

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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 7.5 · High · EPSS 51.5% · Fix available

Published
Updated

Stack: system · web

Affected products and versions

  • apache httpd

    Versions
    • 2.4.47: Affected

    No fix published

  • apache2 Debian:12

    Affected ranges
    • ECOSYSTEM: < 2.4.46-5

    Update to 2.4.46-5

  • apache2 Debian:13

    Affected ranges
    • ECOSYSTEM: < 2.4.46-5

    Update to 2.4.46-5

  • apache2 Debian:14

    Affected ranges
    • ECOSYSTEM: < 2.4.46-5

    Update to 2.4.46-5

Original sources

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