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Vulnerability Details : CVE-2021-31618

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.
Publish Date : 2021-06-15 Last Update Date : 2021-09-20
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- CVSS Scores & Vulnerability Types

CVSS Score
Confidentiality Impact None (There is no impact to the confidentiality of the system.)
Integrity Impact None (There is no impact to the integrity of the system)
Availability Impact Partial (There is reduced performance or interruptions in resource availability.)
Access Complexity Low (Specialized access conditions or extenuating circumstances do not exist. Very little knowledge or skill is required to exploit. )
Authentication Not required (Authentication is not required to exploit the vulnerability.)
Gained Access None
Vulnerability Type(s)
CWE ID 476

- Products Affected By CVE-2021-31618

# Product Type Vendor Product Version Update Edition Language
1 Application Apache Http Server 1.15.17 * * * Version Details Vulnerabilities
2 Application Apache Http Server 2.4.47 * * * Version Details Vulnerabilities
3 OS Debian Debian Linux 9.0 * * * Version Details Vulnerabilities
4 OS Debian Debian Linux 10.0 * * * Version Details Vulnerabilities
5 OS Fedoraproject Fedora 33 * * * Version Details Vulnerabilities
6 OS Fedoraproject Fedora 34 * * * Version Details Vulnerabilities

- Number Of Affected Versions By Product

Vendor Product Vulnerable Versions
Apache Http Server 2
Debian Debian Linux 2
Fedoraproject Fedora 2

- References For CVE-2021-31618 CONFIRM
GENTOO GLSA-202107-38
MLIST [debian-lts-announce] 20210709 [SECURITY] [DLA 2706-1] apache2 security update[email protected]/message/2NKJ3ZA3FTSZ2QBBPKS6BYGAWYRABNQQ/
FEDORA FEDORA-2021-051639aad4
MLIST [oss-security] 20210609 CVE-2021-31618: Apache httpd: NULL pointer dereference on specially crafted HTTP/2 request[email protected]/message/A73QJ4HPUMU26I6EULG6SCK67TUEXZYR/
FEDORA FEDORA-2021-181f29c392[email protected]
MLIST [httpd-cvs] 20210615 svn commit: r1890801 - /httpd/site/trunk/content/security/json/CVE-2021-31618.json[email protected]
MLIST [httpd-cvs] 20210615 svn commit: r1075782 - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2021-31618.json security/vulnerabilities_24.html

- Metasploit Modules Related To CVE-2021-31618

There are not any metasploit modules related to this CVE entry (Please visit for more information)

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