Description
Memcached version 1.5.5 contains an Insufficient Control of Network Message Volume (Network Amplification, CWE-406) vulnerability in the UDP support of the memcached server that can result in denial of service via network flood (traffic amplification of 1:50,000 has been reported by reliable sources). This attack appear to be exploitable via network connectivity to port 11211 UDP. This vulnerability appears to have been fixed in 1.5.6 due to the disabling of the UDP protocol by default.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | memcached | 1.5.6-1 | — |
| Debian 13 | memcached | 1.5.6-1 | — |
| Debian 12 | memcached | 1.5.6-1 | — |
| Debian 9 | memcached | 1.4.33-1+deb9u1 | DSA-4218-1 |
| Debian 8 | memcached | 1.4.21-1.1+deb8u2 | DSA-4218-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | memcached | 1.4.25-2ubuntu1.3 | USN-3588-1 |
| Ubuntu 14.04 LTS | memcached | 1.4.14-0ubuntu9.2 | USN-3588-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Openstack-director 9 | instack-undercloud | 4.0.0-18.el7ost | RHBA-2018:2140 |
| Red Hat Openstack-director 9 | openstack-tripleo-heat-templates +1 | 2.0.0-65.el7ost | RHBA-2018:2140 |
| Red Hat Openstack-director 8 | instack-undercloud | 2.2.7-13.el7ost | RHSA-2018:2857 |
| Red Hat Openstack-director 8 | openstack-tripleo-heat-templates +1 | 0.8.14-42.el7ost | RHSA-2018:2857 |
| Red Hat OpenStack 12 | instack-undercloud | 7.4.12-1.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | openstack-tripleo-common +3 | 7.6.13-3.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | openstack-tripleo-heat-templates | 7.0.12-8.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | openstack-tripleo-image-elements | 7.0.5-1.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | openstack-tripleo-puppet-elements | 7.0.7-1.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | os-net-config | 7.3.6-1.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | puppet-aodh +3 | 11.4.0-2.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | puppet-ceph | 2.4.2-2.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | puppet-heat +5 | 11.5.0-2.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | puppet-manila | 11.4.0-4.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | puppet-nova +1 | 11.5.0-4.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | puppet-tripleo | 7.4.12-8.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | python-novajoin | 1.0.17-3.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | python-os-brick | 1.15.5-2.el7ost | RHSA-2018:2331 |
| Red Hat OpenStack 12 | python-tripleoclient | 7.3.10-3.el7ost | RHSA-2018:2331 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat OpenStack 11 | openstack-tripleo-heat-templates | 6.2.12-2.el7ost | RHSA-2018:1627 |
| Red Hat OpenStack 11 | puppet-tripleo | 6.5.10-3.el7ost | RHSA-2018:1627 |
| Red Hat OpenStack 10 | openstack-tripleo-heat-templates | 5.3.10-1.el7ost | RHSA-2018:1593 |
| Red Hat OpenStack 10 | puppet-tripleo | 5.6.8-6.el7ost | RHSA-2018:1593 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | memcached | 1.4.39-4.6.1 | SUSE-SU-2018:0955-1 |
| SLES 11 SP4 | memcached | 1.2.6-5.17.3.1 | SUSE-SU-2018:1326-1 |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Studio Onsite Runner 1.3 | memcached | 1.2.6-5.17.3.1 | SUSE-SU-2018:1326-1 |
| SUSE Studio Onsite 1.3 | memcached | 1.2.6-5.17.3.1 | SUSE-SU-2018:1326-1 |
| SLES for SAP 12 SP3 | memcached | 1.4.39-4.6.1 | SUSE-SU-2018:0955-1 |
| SUSE OpenStack Cloud 7 | ansible | 2.2.3.0-12.2 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | crowbar-core | 4.0+git.1580209654.1d112d31f-9.66.5 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | crowbar-ha | 4.0+git.1521473535.67d2302-4.28.1 | SUSE-RU-2020:2072-1, SUSE-RU-2018:1071-1 |
| SUSE OpenStack Cloud 7 | crowbar-openstack | 4.0+git.1522325467.43e431f91-9.30.1 | SUSE-RU-2020:2072-1, SUSE-RU-2018:1071-1 |
| SUSE OpenStack Cloud 7 | grafana | 4.6.5-1.14.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | keepalived | 2.0.19-1.8.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | kibana | 4.6.3-5.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | memcached | 1.5.17-3.6.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | monasca-installer | 20180608_12.47-12.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | openstack-dashboard-theme-SUSE | 2016.2-5.12.4 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | openstack-manila | 3.0.1~dev30-4.12.2 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | openstack-manila-doc | 3.0.1~dev30-4.12.3 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | openstack-neutron-fwaas | 9.0.2~dev5-4.9.3 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | openstack-neutron-fwaas-doc | 9.0.2~dev5-4.9.4 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | openstack-nova +1 | 14.0.11~dev13-4.40.2 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | openstack-tempest | 12.2.1~a0~dev177-4.9.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | python-Django | 1.8.19-3.23.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | python-Pillow | 2.8.1-4.12.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | python-psql2mysql | 0.5.0+git.1589351878.4ef877c-1.12.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | python-psutil | 1.2.1-21.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | python-py | 1.8.1-11.12.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | python-pysaml2 | 4.0.2-3.17.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | python-waitress | 1.4.3-3.3.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | rabbitmq-server | 3.4.4-3.16.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | release-notes-suse-openstack-cloud | 7.20180803-3.18.3 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | rubygem-activeresource | 4.0.0-3.3.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | rubygem-crowbar-client | 3.9.2-7.20.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | rubygem-json-1_7 | 1.7.7-3.3.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | rubygem-puma | 2.16.0-4.6.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 7 | zookeeper | 3.4.10-6.1 | SUSE-RU-2020:2072-1 |
| SUSE OpenStack Cloud 6 | crowbar-openstack | 3.0+git.1521471181.2b39130da-39.10.1 | SUSE-SU-2018:1103-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | memcached | 1.6.9-2.3 | openSUSE-SU-2024:11045-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.6 | memcached | 1.4.36-r2 | — |
| Alpine v3.5 | memcached | 1.4.33-r2 | — |
| Alpine v3.4 | memcached | 1.4.33-r2 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | memcached +1 | 1.4.15-10.amzn2.1.1 | ALAS2-2018-964 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.
Metasploit 1 module
-
Memcached Stats Amplification Scanner
auxiliary/scanner/memcached/memcached_amp
Exploit-DB 2
- Memcached 1.5.5 - 'Memcrashed ' Insufficient Control of Network Message Volume Denial of Service With Shodan API EDB-44265 · dos · Mar 8, 2018
- Memcached 1.5.5 - 'Memcrashed' Insufficient Control Network Message Volume Denial of Service (1) EDB-44264 · dos · Mar 5, 2018
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 14
- RHSA-2018:2857 Red Hat Security Advisory: Red Hat OpenStack Platform 8 director security and bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2018:2331 Red Hat Security Advisory: Red Hat OpenStack Platform 12.0 director security and bug fix update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2018:1593 Red Hat Security Advisory: Red Hat OpenStack Platform director security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2018:1627 Red Hat Security Advisory: Red Hat OpenStack Platform director security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHBA-2018:2140 Red Hat Bug Fix Advisory: Red Hat OpenStack Platform 9 director Bug Fix Advisory Red Hat Security Advisories (RHSA) · Jun 29, 2026
- DSA-4218-1 memcached - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-3588-1 memcached vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- openSUSE-SU-2024:11045-1 memcached-1.6.9-2.3 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:0955-1 Security update for memcached SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:1326-1 Security update for memcached SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:1103-1 Security update for crowbar-openstack SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-RU-2020:2072-1 Security update for ansible, crowbar-core, crowbar-ha, crowbar-openstack, etcd, flannel, grafana, keepalived, kibana, memcached, monasca-installer, openstack-dashboard-theme-SUSE, openstack-manila, openstack-neutron-fwaas, openstack-nova, openstack-tempest, python-Django, python-Pillow, python-psql2mysql, python-psutil, python-py, python-pysaml2, python-waitress, rabbitmq-server, release-notes-suse-openstack-cloud, zookeeper SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-RU-2018:1071-1 Recommended update for several crowbar barclamps SUSE / openSUSE Security Updates · Feb 4, 2026
- ALAS2-2018-964 Moderate: memcached security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · May 29, 2018
References
- RHBA-2018:2140 vendor-advisory
- RHSA-2018:1593 vendor-advisory
- USN-3588-1 vendor-advisory
- https://github.com/memcached/memcached/wiki/ReleaseNotes156
- 44264 exploit
- https://twitter.com/dormando/status/968579781729009664
- 44265 exploit
- https://github.com/memcached/memcached/commit/dbb7a8af90054bf4ef51f5814ef7ceb17d83d974
- RHSA-2018:2857 vendor-advisory
- RHSA-2018:1627 vendor-advisory
- RHSA-2018:2331 vendor-advisory
- DSA-4218 vendor-advisory
- https://blogs.akamai.com/2018/03/memcached-fueled-13-tbps-attacks.html
- https://github.com/memcached/memcached/issues/348
- https://www.synology.com/support/security/Synology_SA_18_07