CVE-2016-1546

Severity: medium (CVSS 5.9 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 15.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2016-07-06 · updated 2026-06-17
Weakness: CWE-399

Description

The Apache HTTP Server 2.4.17 and 2.4.18, when mod_http2 is enabled, does not limit the number of simultaneous stream workers for a single HTTP/2 connection, which allows remote attackers to cause a denial of service (stream-processing outage) via modified flow-control windows.

Affected products

Apache HTTP Server: 2.4.17, 2.4.18

References

http://httpd.apache.org/security/vulnerabilities_24.html
http://svn.apache.org/viewvc?view=revision&revision=1733727
http://www.apache.org/dist/httpd/CHANGES_2.4
http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.html
http://www.oracle.com/technetwork/topics/security/bulletinoct2016-3090566.html
http://www.securityfocus.com/bid/92331
https://access.redhat.com/errata/RHSA-2017:1161
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
https://lists.apache.org/thread.html/r76142b8c5119df2178be7c2dba88fde552eedeec37ea993dfce68d1d%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r9f93cf6dde308d42a9c807784e8102600d0397f5f834890708bf6920%40%3Ccvs.httpd.apache.org%3E

Get alerted when CVE-2016-1546 or the next vulnerability affects your stack