CVE-2017-9789

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 9.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2017-07-13 · updated 2026-06-17
Weakness: CWE-416

Description

When under stress, closing many connections, the HTTP/2 handling code in Apache httpd 2.4.26 would sometimes access memory after it has been freed, resulting in potentially erratic behaviour.

Affected products

Apache HTTP Server: 2.4.26

References

http://www.securityfocus.com/bid/99568
http://www.securitytracker.com/id/1038907
https://httpd.apache.org/security/vulnerabilities_24.html
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/9d0098775bd83cf7c33ac5a077ef412c14ce939198921e639c734e20%40%3Cannounce.httpd.apache.org%3E
https://lists.apache.org/thread.html/r15f9aa4427581a1aecb4063f1b4b983511ae1c9935e2a0a6876dad3c%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r476d175be0aaf4a17680ef98c5153b4d336eaef76fb2224cc94c463a%40%3Ccvs.httpd.apache.org%3E
https://lists.apache.org/thread.html/r6521a7f62276340eabdb3339b2aa9a38c5f59d978497a1f794af53be%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
https://lists.apache.org/thread.html/rc998b18880df98bafaade071346690c2bc1444adaa1a1ea464b93f0a%40%3Ccvs.httpd.apache.org%3E

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