CVE-2018-11763
In Apache HTTP Server 2.4.17 to 2.4.34, by sending continuous, large SETTINGS frames a client can occupy a connection, server thread and CPU time without any connection timeout coming to effect.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 50.8%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
Description
In Apache HTTP Server 2.4.17 to 2.4.34, by sending continuous, large SETTINGS frames a client can occupy a connection, server thread and CPU time without any connection timeout coming to effect. This affects only HTTP/2 connections. A possible mitigation is to not enable the h2 protocol.
- CVSS 3.0
- 5.9 MEDIUMCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 50.85% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Affected
- apache/http server · canonical/ubuntu linux · redhat/enterprise linux · oracle/enterprise manager ops center · oracle/hospitality guest access · oracle/instantis enterprisetrack · oracle/retail xstore point of service · oracle/secure global desktop · netapp/storage automation store
- Source
- security@apache.org
EPSS moved from 45.3% on 21 September 2026 to 50.8% on 28 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
References
- http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00030.html
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00056.html
- http://www.securityfocus.com/bid/105414Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1041713Third Party Advisory, VDB Entry
- https://access.redhat.com/errata/RHSA-2018:3558Third Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0366Third Party Advisory
- https://access.redhat.com/errata/RHSA-2019:0367Third Party Advisory
- https://httpd.apache.org/security/vulnerabilities_24.htmlVendor Advisory
- 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/r06f0d87ebb6d59ed8379633f36f72f5b1f79cadfda72ede0830b42cf%40%3Ccvs.httpd.apache.org%3E
- https://lists.apache.org/thread.html/r15f9aa4427581a1aecb4063f1b4b983511ae1c9935e2a0a6876dad3c%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
- https://lists.apache.org/thread.html/rd18c3c43602e66f9cdcf09f1de233804975b9572b0456cc582390b6f%40%3Ccvs.httpd.apache.org%3E
- https://lists.apache.org/thread.html/re3d27b6250aa8548b8845d314bb8a350b3df326cacbbfdfe4d455234%40%3Ccvs.httpd.apache.org%3E
- https://lists.apache.org/thread.html/rf6449464fd8b7437704c55f88361b66f12d5b5f90bcce66af4be4ba9%40%3Ccvs.httpd.apache.org%3E
- https://lists.apache.org/thread.html/rfcf929bd33a6833e3f0c35eebdad70d5060665f9c4e17ea467c66770%40%3Ccvs.httpd.apache.org%3E
- https://security.netapp.com/advisory/ntap-20190204-0004/Third Party Advisory
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03909en_usThird Party Advisory
- https://usn.ubuntu.com/3783-1/Third Party Advisory
- https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.htmlPatch, Third Party Advisory
- https://www.oracle.com/technetwork/security-advisory/cpujan2019-5072801.htmlPatch, Third Party Advisory
- https://www.tenable.com/security/tns-2019-09
- http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00030.html
- http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00056.html
- http://www.securityfocus.com/bid/105414Third Party Advisory, VDB Entry
- http://www.securitytracker.com/id/1041713Third Party Advisory, VDB Entry
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.