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Fencer Intel
medium 5.3

CVE-2018-17189 json

In Apache HTTP server versions 2.4.37 and prior, by sending request bodies in a slow loris way to plain resources, the h2 stream for that r…

published 7y ago modified 4mo ago also EUVD-2018-8960

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
19.4%
EPSS 19.4% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

In Apache HTTP server versions 2.4.37 and prior, by sending request bodies in a slow loris way to plain resources, the h2 stream for that request unnecessarily occupied a server thread cleaning up that incoming data. This affects only HTTP/2 (mod_http2) connections.

Patch / fix

  • apache2 Debian 14, Debian 13, Debian 12 2.4.38-1

debian advisories DEBIAN-CVE-2018-17189

  • apache2 Ubuntu 18.04 LTS 2.4.29-1ubuntu4.6

ubuntu advisories UBUNTU-CVE-2018-17189

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

  • httpd RHEL 8 2.4.37-30.module+el8.3.0+7001+0766b9e7
  • mod_md RHEL 8 1:2.0.8-8.module+el8.3.0+6814+67d1e611
  • mod_ssl RHEL 8 1:2.4.37-30.module+el8.3.0+7001+0766b9e7
  • mod_ldap RHEL 8 2.4.37-30.module+el8.3.0+7001+0766b9e7
  • mod_http2 RHEL 8 1.15.7-2.module+el8.3.0+7670+8bf57d29
  • httpd-tools RHEL 8 2.4.37-30.module+el8.3.0+7001+0766b9e7
  • mod_session RHEL 8 2.4.37-30.module+el8.3.0+7001+0766b9e7
  • httpd-manual RHEL 8 2.4.37-30.module+el8.3.0+7001+0766b9e7

red hat advisories RHSA-2020:4751RHSA-2019:4126RHSA-2019:3932RHSA-2019:3933

  • apache2 SLE Module for Server Applications 15 2.4.33-3.9.7
  • apache2 SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES 12 SP4 +3 more 2.4.23-29.34.4

suse advisories SUSE-SU-2019:0504-1SUSE-SU-2019:0498-1

  • apache2 openSUSE Leap 15.0 2.4.33-lp150.2.9.1

opensuse advisories openSUSE-SU-2019:0296-1

  • mod_md AlmaLinux 8 1:2.0.8-8.module_el8.5.0+2609+b30d9eec
  • mod_md AlmaLinux 8 1:2.0.8-8.module_el8.6.0+2872+fe0ff7aa

almalinux advisories ALSA-2020:4751

  • mod_md Rocky Linux 8 1:2.0.8-8.module+el8.5.0+695+1fa8055e
  • mod_md Rocky Linux 8 1:2.0.8-8.module+el8.4.0+553+7a69454b

rocky linux advisories RLSA-2020:4751

  • apache2 Alpine 3.24, Alpine 3.23, Alpine 3.22 +16 more 2.4.38-r0

alpine advisories ALPINE-CVE-2018-17189

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

  • apache Arch Linux 2.4.38-1

arch linux advisories AVG-857

Is CVE-2018-17189 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2018-17189 updated cvss 4.3

httpd: mod_http2: DoS via slow, unneeded request bodies

  • Red Hat Enterprise Linux AppStream (v. 8) mod_md 2.0.8-8.module+el8.3.0+6814+67d1e611, httpd 2.4.37-30.module+el8.3.0+7001+0766b9e7, mod_ssl 2.4.37-30.module+el8.3.0+7001+0766b9e7, mod_http2 1.15.7-2.module+el8.3.0+7670+8bf57d29, mod_ldap 2.4.37-30.module+el8.3.0+7001+0766b9e7, httpd-tools 2.4.37-30.module+el8.3.0+7001+0766b9e7, +4 more
    fixed: vendor fix RHSA-2020:4751
  • Red Hat JBoss Core Services
    fixed: vendor fix RHSA-2019:3935
  • Red Hat JBoss Core Services on RHEL 6 Server jbcs-httpd24-apr 1.6.3-63.jbcs.el6, jbcs-httpd24-brotli 1.0.6-7.jbcs.el6, jbcs-httpd24-curl 7.64.1-14.jbcs.el6, jbcs-httpd24-httpd 2.4.37-33.jbcs.el6, jbcs-httpd24-jansson 2.11-20.jbcs.el6, jbcs-httpd24-mod_md 2.4.37-33.jbcs.el6, +25 more
    fixed: vendor fix RHSA-2019:3932
  • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-apr 1.6.3-63.jbcs.el7, jbcs-httpd24-brotli 1.0.6-7.jbcs.el7, jbcs-httpd24-curl 7.64.1-14.jbcs.el7, jbcs-httpd24-httpd 2.4.37-33.jbcs.el7, jbcs-httpd24-jansson 2.11-20.jbcs.el7, jbcs-httpd24-mod_md 2.4.37-33.jbcs.el7, +25 more
    fixed: vendor fix RHSA-2019:3933
  • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) httpd24 1.1-19.el6, httpd24-build 1.1-19.el6, httpd24-runtime 1.1-19.el6, httpd24-httpd 2.4.34-15.el6, httpd24-nghttp2 1.7.1-8.el6, httpd24-scldevel 1.1-19.el6, +7 more Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) httpd24 1.1-19.el7, httpd24-runtime 1.1-19.el7, httpd24-httpd 2.4.34-15.el7, httpd24-nghttp2 1.7.1-8.el7, httpd24-scldevel 1.1-19.el7, httpd24-mod_md 2.4.34-15.el7, +7 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.5) httpd24 1.1-19.el7, httpd24-runtime 1.1-19.el7, httpd24-httpd 2.4.34-15.el7, httpd24-nghttp2 1.7.1-8.el7, httpd24-scldevel 1.1-19.el7, httpd24-mod_md 2.4.34-15.el7, +7 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.6) httpd24 1.1-19.el7, httpd24-runtime 1.1-19.el7, httpd24-httpd 2.4.34-15.el7, httpd24-nghttp2 1.7.1-8.el7, httpd24-scldevel 1.1-19.el7, httpd24-mod_md 2.4.34-15.el7, +7 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7) httpd24 1.1-19.el7, httpd24-runtime 1.1-19.el7, httpd24-httpd 2.4.34-15.el7, httpd24-nghttp2 1.7.1-8.el7, httpd24-scldevel 1.1-19.el7, httpd24-mod_md 2.4.34-15.el7, +7 more Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) httpd24 1.1-19.el6, httpd24-build 1.1-19.el6, httpd24-runtime 1.1-19.el6, httpd24-httpd 2.4.34-15.el6, httpd24-nghttp2 1.7.1-8.el6, httpd24-scldevel 1.1-19.el6, +7 more
    +1 more products
    Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) httpd24 1.1-19.el7, httpd24-runtime 1.1-19.el7, httpd24-httpd 2.4.34-15.el7, httpd24-nghttp2 1.7.1-8.el7, httpd24-scldevel 1.1-19.el7, httpd24-mod_md 2.4.34-15.el7, +7 more
    fixed: vendor fix RHSA-2019:4126
  • Red Hat CloudForms Management Engine 5 httpd Red Hat Enterprise Linux 5 httpd 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 JBoss Enterprise Application Platform 5 httpd Red Hat JBoss Enterprise Application Platform 6 httpd, mod_ssl, mod_ldap, httpd-tools, httpd-manual
    +3 more products
    Red Hat JBoss Enterprise Web Server 2 jbcs-httpd24, jbcs-httpd24-runtime Red Hat JBoss Web Server 3 httpd24 Red Hat Virtualization 4 rhvm-appliance
    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

19.40% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • Apache Software Foundation Apache HTTP Server

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
Technology feeds

References

Sources

Fencer Intel 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.