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Fencer Vulns
medium 5.9

CVE-2018-11763 json

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 CP…

published 2018-09-25 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-3778

cvss
5.9
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
51.0%
EPSS 51.0% chance of exploitation in 30 days, percentile 98%
public exploits
0
none known

Summary

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.

Patch / fix

  • apache2 Debian 14, Debian 13, Debian 12 2.4.35-1

debian advisories DEBIAN-CVE-2018-11763

  • apache2 Ubuntu 18.04 LTS 2.4.29-1ubuntu4.4

ubuntu advisories UBUNTU-CVE-2018-11763

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • jbcs-httpd24 jboss core services 1 1-6.jbcs.el6
  • jbcs-httpd24 jboss core services 1 1-6.jbcs.el7
  • jbcs-httpd24-apr jboss core services 1 1.6.3-31.jbcs.el6
  • jbcs-httpd24-apr jboss core services 1 1.6.3-31.jbcs.el7
  • jbcs-httpd24-httpd jboss core services 1 2.4.29-35.jbcs.el6
  • jbcs-httpd24-httpd jboss core services 1 2.4.29-35.jbcs.el7
  • jbcs-httpd24-mod_jk jboss core services 1 1.2.46-1.redhat_1.jbcs.el6
  • jbcs-httpd24-mod_jk jboss core services 1 1.2.46-1.redhat_1.jbcs.el7

red hat advisories RHSA-2019:0367RHSA-2018:3558

  • apache2 SLES 12 SP4, SLES 12 SP3, SLES 12 SP2-BCL +8 more 2.4.23-29.27.2
  • apache2 SLE Module for Server Applications 15 2.4.33-3.6.1

suse advisories SUSE-SU-2018:3582-2SUSE-SU-2018:3582-1SUSE-SU-2018:3101-1

  • virtualbox openSUSE Tumbleweed 6.1.26-3.2
  • virtualbox openSUSE Leap 15.1, openSUSE Leap 15.0 6.0.10-lp151.2.6.1
  • virtualbox openSUSE Leap 15.0 5.2.24-lp150.4.33.1

opensuse advisories openSUSE-SU-2024:11501-1openSUSE-SU-2019:1814-1openSUSE-SU-2019:1547-1

  • apache2 Alpine 3.24, Alpine 3.23, Alpine 3.22 +17 more 2.4.35-r0

alpine advisories ALPINE-CVE-2018-11763

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-11763 updated cvss 7.5

httpd: DoS for HTTP/2 connections by continuous SETTINGS frames

  • Red Hat Mobile Application Platform 4 httpd
    affected: no fix planned “Will not fix”
  • Red Hat JBoss Core Services
    fixed: vendor fix RHSA-2019:0366
  • Red Hat JBoss Core Services on RHEL 6 Server jbcs-httpd24 1-6.jbcs.el6, jbcs-httpd24-runtime 1-6.jbcs.el6, jbcs-httpd24-apr 1.6.3-31.jbcs.el6, jbcs-httpd24-httpd 2.4.29-35.jbcs.el6, jbcs-httpd24-nghttp2 1.29.0-9.jbcs.el6, jbcs-httpd24-apr-util 1.6.1-24.jbcs.el6, +22 more Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24 1-6.jbcs.el7, jbcs-httpd24-runtime 1-6.jbcs.el7, jbcs-httpd24-apr 1.6.3-31.jbcs.el7, jbcs-httpd24-httpd 2.4.29-35.jbcs.el7, jbcs-httpd24-nghttp2 1.29.0-9.jbcs.el7, jbcs-httpd24-apr-util 1.6.1-24.jbcs.el7, +22 more
    fixed: vendor fix RHSA-2019:0367
  • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) httpd24-curl 7.61.1-1.el6, httpd24-httpd 2.4.34-7.el6, httpd24-nghttp2 1.7.1-7.el6, httpd24-libcurl 7.61.1-1.el6, httpd24-mod_ssl 2.4.34-7.el6, httpd24-mod_ldap 2.4.34-7.el6, +5 more Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) httpd24-curl 7.61.1-1.el7, httpd24-httpd 2.4.34-7.el7, httpd24-mod_md 2.4.34-7.el7, httpd24-nghttp2 1.7.1-7.el7, httpd24-libcurl 7.61.1-1.el7, httpd24-mod_ssl 2.4.34-7.el7, +6 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.4) httpd24-curl 7.61.1-1.el7, httpd24-httpd 2.4.34-7.el7, httpd24-mod_md 2.4.34-7.el7, httpd24-nghttp2 1.7.1-7.el7, httpd24-libcurl 7.61.1-1.el7, httpd24-mod_ssl 2.4.34-7.el7, +6 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.5) httpd24-curl 7.61.1-1.el7, httpd24-httpd 2.4.34-7.el7, httpd24-mod_md 2.4.34-7.el7, httpd24-nghttp2 1.7.1-7.el7, httpd24-libcurl 7.61.1-1.el7, httpd24-mod_ssl 2.4.34-7.el7, +6 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.6) httpd24-curl 7.61.1-1.el7, httpd24-httpd 2.4.34-7.el7, httpd24-mod_md 2.4.34-7.el7, httpd24-nghttp2 1.7.1-7.el7, httpd24-libcurl 7.61.1-1.el7, httpd24-mod_ssl 2.4.34-7.el7, +6 more Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) httpd24-curl 7.61.1-1.el6, httpd24-httpd 2.4.34-7.el6, httpd24-nghttp2 1.7.1-7.el6, httpd24-libcurl 7.61.1-1.el6, httpd24-mod_ssl 2.4.34-7.el6, httpd24-mod_ldap 2.4.34-7.el6, +5 more
    +1 more products
    Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) httpd24-curl 7.61.1-1.el7, httpd24-httpd 2.4.34-7.el7, httpd24-mod_md 2.4.34-7.el7, httpd24-nghttp2 1.7.1-7.el7, httpd24-libcurl 7.61.1-1.el7, httpd24-mod_ssl 2.4.34-7.el7, +6 more
    fixed: vendor fix RHSA-2018:3558
  • Red Hat Enterprise Linux 6 httpd, mod_ssl, httpd-tools, httpd-manual Red Hat Enterprise Linux 7 httpd, mod_ssl, mod_ldap, httpd-tools, mod_session, httpd-manual, +1 more Red Hat Enterprise Linux 8 httpd, mod_md, mod_ssl, mod_ldap, mod_http2, httpd-tools, +4 more Red Hat JBoss Enterprise Application Platform 5 httpd Red Hat JBoss Enterprise Application Platform 6 httpd, mod_ssl, mod_ldap, httpd-tools, httpd-manual Red Hat JBoss Enterprise Web Server 2 jbcs-httpd24, jbcs-httpd24-runtime
    +2 more products
    Red Hat JBoss Web Server 3 httpd24 Red Hat Virtualization 4 httpd
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

51.00% chance of exploitation in the next 30 days, higher than 98% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 5.9 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:N/A:P

Affected products

  • Apache Software Foundation Apache HTTP Server

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.