CVE-2016-8740

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 79.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2016-12-05 · updated 2026-06-17
Weakness: CWE-20

Description

The mod_http2 module in the Apache HTTP Server 2.4.17 through 2.4.23, when the Protocols configuration includes h2 or h2c, does not restrict request-header length, which allows remote attackers to cause a denial of service (memory consumption) via crafted CONTINUATION frames in an HTTP/2 request.

Affected products

Apache HTTP Server: 2.4.17, 2.4.18, 2.4.19, 2.4.20, 2.4.21, 2.4.22 (+1)

References

http://packetstormsecurity.com/files/140023/Apache-HTTPD-Web-Server-2.4.23-Memory-Exhaustion.html
http://rhn.redhat.com/errata/RHSA-2017-1415.html
http://www.securityfocus.com/bid/94650
http://www.securitytracker.com/id/1037388
https://access.redhat.com/errata/RHSA-2017:1161
https://access.redhat.com/errata/RHSA-2017:1413
https://access.redhat.com/errata/RHSA-2017:1414
https://github.com/apache/httpd/commit/29c63b786ae028d82405421585e91283c8fa0da3
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03725en_us
https://lists.apache.org/thread.html/56c2e7cc9deb1c12a843d0dc251ea7fd3e7e80293cde02fcd65286ba%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/84a3714f0878781f6ed84473d1a503d2cc382277e100450209231830%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r04e89e873d54116a0635ef2f7061c15acc5ed27ef7500997beb65d6f%40%3Ccvs.httpd.apache.org%3E

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