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Fencer Intel
high 7.5

CVE-2016-2161 in the critical feed json

In Apache HTTP Server versions 2.4.0 to 2.4.23, malicious input to mod_auth_digest can cause the server to crash, and each instance continu…

published 2017-07-27 9 y ago modified 2026-06-17 4 mo ago also EUVD-2016-3253

cvss
7.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
21.0%
EPSS 21.0% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

In Apache HTTP Server versions 2.4.0 to 2.4.23, malicious input to mod_auth_digest can cause the server to crash, and each instance continues to crash even for subsequently valid requests.

Patch / fix

  • apache2 Debian 14, Debian 13, Debian 12 2.4.25-1

debian advisories DEBIAN-CVE-2016-2161

  • apache2 Ubuntu 14.04 LTS 2.4.7-1ubuntu4.15
  • apache2 Ubuntu 16.04 LTS 2.4.18-2ubuntu3.2

ubuntu advisories UBUNTU-CVE-2016-2161

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

  • httpd24-httpd RHEL 2 SOFTWARE_COLLECTIONS 2.4.25-9.el6
  • httpd24-httpd RHEL 2 SOFTWARE_COLLECTIONS 2.4.25-9.el7
  • httpd24-mod_ssl RHEL 2 SOFTWARE_COLLECTIONS 1:2.4.25-9.el6
  • httpd24-mod_ssl RHEL 2 SOFTWARE_COLLECTIONS 1:2.4.25-9.el7
  • httpd24-mod_ldap RHEL 2 SOFTWARE_COLLECTIONS 2.4.25-9.el6
  • httpd24-mod_ldap RHEL 2 SOFTWARE_COLLECTIONS 2.4.25-9.el7
  • httpd24-httpd-tools RHEL 2 SOFTWARE_COLLECTIONS 2.4.25-9.el6
  • httpd24-httpd-tools RHEL 2 SOFTWARE_COLLECTIONS 2.4.25-9.el7

red hat advisories RHSA-2017:1161RHSA-2017:1414RHSA-2017:1413RHSA-2017:0906

  • apache2 SLES for SAP 12 SP2, SLES for Raspberry Pi 12 SP2, SLES 12 SP2 +1 more 2.4.23-21.1
  • apache2 SLES for SAP 12 SP1, SLES 12 SP1, SLE Software Development Kit 12 SP1 2.4.16-19.1
  • apache2 Studio Onsite 1.3, SLES for SAP 11 SP4, SLES 11 SP4 +1 more 2.2.12-69.1

suse advisories SUSE-SU-2017:0797-1SUSE-SU-2017:0801-1SUSE-SU-2017:0729-1

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-2016-2161 updated cvss 7.5

httpd: DoS vulnerability in mod_auth_digest

  • Red Hat Enterprise Linux Client Optional (v. 7) httpd 2.4.6-45.el7_3.4, mod_ssl 2.4.6-45.el7_3.4, mod_ldap 2.4.6-45.el7_3.4, httpd-tools 2.4.6-45.el7_3.4, mod_session 2.4.6-45.el7_3.4, httpd-manual 2.4.6-45.el7_3.4, +1 more Red Hat Enterprise Linux ComputeNode Optional (v. 7) httpd 2.4.6-45.el7_3.4, mod_ssl 2.4.6-45.el7_3.4, mod_ldap 2.4.6-45.el7_3.4, httpd-tools 2.4.6-45.el7_3.4, mod_session 2.4.6-45.el7_3.4, httpd-manual 2.4.6-45.el7_3.4, +1 more Red Hat Enterprise Linux Server (v. 7) httpd 2.4.6-45.el7_3.4, mod_ssl 2.4.6-45.el7_3.4, httpd-tools 2.4.6-45.el7_3.4, httpd-manual 2.4.6-45.el7_3.4 Red Hat Enterprise Linux Server Optional (v. 7) mod_ldap 2.4.6-45.el7_3.4, mod_session 2.4.6-45.el7_3.4, mod_proxy_html 2.4.6-45.el7_3.4 Red Hat Enterprise Linux Workstation (v. 7) httpd 2.4.6-45.el7_3.4, mod_ssl 2.4.6-45.el7_3.4, httpd-tools 2.4.6-45.el7_3.4, httpd-manual 2.4.6-45.el7_3.4 Red Hat Enterprise Linux Workstation Optional (v. 7) mod_ldap 2.4.6-45.el7_3.4, mod_session 2.4.6-45.el7_3.4, mod_proxy_html 2.4.6-45.el7_3.4
    fixed: vendor fix RHSA-2017:0906
  • Red Hat JBoss Core Services
    fixed: vendor fix RHSA-2017:1415
  • Red Hat JBoss Core Services on RHEL 6 Server jbcs-httpd24-httpd 2.4.23-120.jbcs.el6, jbcs-httpd24-openssl 1.0.2h-13.jbcs.el6, jbcs-httpd24-mod_ssl 2.4.23-120.jbcs.el6, jbcs-httpd24-mod_ldap 2.4.23-120.jbcs.el6, jbcs-httpd24-httpd-libs 2.4.23-120.jbcs.el6, jbcs-httpd24-httpd-tools 2.4.23-120.jbcs.el6, +7 more
    fixed: vendor fix RHSA-2017:1414
  • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-httpd 2.4.23-120.jbcs.el7, jbcs-httpd24-openssl 1.0.2h-13.jbcs.el7, jbcs-httpd24-mod_ssl 2.4.23-120.jbcs.el7, jbcs-httpd24-mod_ldap 2.4.23-120.jbcs.el7, jbcs-httpd24-httpd-libs 2.4.23-120.jbcs.el7, jbcs-httpd24-httpd-tools 2.4.23-120.jbcs.el7, +7 more
    fixed: vendor fix RHSA-2017:1413
  • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 6) httpd24-httpd 2.4.25-9.el6, httpd24-mod_ssl 2.4.25-9.el6, httpd24-mod_ldap 2.4.25-9.el6, httpd24-httpd-tools 2.4.25-9.el6, httpd24-mod_session 2.4.25-9.el6, httpd24-httpd-manual 2.4.25-9.el6, +1 more Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) httpd24-httpd 2.4.25-9.el7, httpd24-mod_ssl 2.4.25-9.el7, httpd24-mod_ldap 2.4.25-9.el7, httpd24-httpd-tools 2.4.25-9.el7, httpd24-mod_session 2.4.25-9.el7, httpd24-httpd-manual 2.4.25-9.el7, +1 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 6.7) httpd24-httpd 2.4.25-9.el6, httpd24-mod_ssl 2.4.25-9.el6, httpd24-mod_ldap 2.4.25-9.el6, httpd24-httpd-tools 2.4.25-9.el6, httpd24-mod_session 2.4.25-9.el6, httpd24-httpd-manual 2.4.25-9.el6, +1 more Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.3) httpd24-httpd 2.4.25-9.el7, httpd24-mod_ssl 2.4.25-9.el7, httpd24-mod_ldap 2.4.25-9.el7, httpd24-httpd-tools 2.4.25-9.el7, httpd24-mod_session 2.4.25-9.el7, httpd24-httpd-manual 2.4.25-9.el7, +1 more Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 6) httpd24-httpd 2.4.25-9.el6, httpd24-mod_ssl 2.4.25-9.el6, httpd24-mod_ldap 2.4.25-9.el6, httpd24-httpd-tools 2.4.25-9.el6, httpd24-mod_session 2.4.25-9.el6, httpd24-httpd-manual 2.4.25-9.el6, +1 more Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) httpd24-httpd 2.4.25-9.el7, httpd24-mod_ssl 2.4.25-9.el7, httpd24-mod_ldap 2.4.25-9.el7, httpd24-httpd-tools 2.4.25-9.el7, httpd24-mod_session 2.4.25-9.el7, httpd24-httpd-manual 2.4.25-9.el7, +1 more
    fixed: vendor fix RHSA-2017:1161
  • Red Hat Directory Server 8 httpd Red Hat Enterprise Linux 5 httpd Red Hat Enterprise Linux 6 httpd, mod_ssl, httpd-tools, httpd-manual Red Hat JBoss Enterprise Application Platform 5 httpd Red Hat JBoss Enterprise Application Platform 6 httpd, mod_ssl, mod_ldap, httpd-tools, httpd-manual, httpd22 httpd22 Red Hat JBoss Enterprise Web Server 1 httpd
    +2 more products
    Red Hat JBoss Enterprise Web Server 2 jbcs-httpd24, httpd22 httpd22, jbcs-httpd24-runtime Red Hat JBoss Web Server 3 httpd24
    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

20.95% 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 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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-823 Use of Out-of-range Pointer Offset
  • CWE-20 Improper Input Validation
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.