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OpenAdvisories
High · 7.5 Public exploit CVE-2021-32675 EUVD-2021-19484

DoS vulnerability in Redis

Published Oct 4, 2021 · Updated Aug 3, 2024 · Assigned by GitHub_M

Vendor: Redis Product: Redis Package: redis Package: redis Package: redis Package: redis Ecosystem: Alpine Ecosystem: Azure Linux Ecosystem: Debian Ecosystem: Ubuntu

Description

Redis is an open source, in-memory database that persists on disk. When parsing an incoming Redis Standard Protocol (RESP) request, Redis allocates memory according to user-specified values which determine the number of elements (in the multi-bulk header) and size of each element (in the bulk header). An attacker delivering specially crafted requests over multiple connections can cause the server to allocate significant amount of memory. Because the same parsing mechanism is used to handle authentication requests, this vulnerability can also be exploited by unauthenticated users. The problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14. An additional workaround to mitigate this problem without patching the redis-server executable is to block access to prevent unauthenticated users from connecting to Redis. This can be done in different ways: Using network access control tools like firewalls, iptables, security groups, etc. or Enabling TLS and requiring users to authenticate using client side certificates.

Affected products

VendorProductAffectedFixed
redis redis < 5.0.14, >= 6.0.0, < 6.0.16, >= 6.2.0, < 6.2.6 —

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 ↗
ReleasePackageFixed inAdvisory
Debian 14 redis 5:6.0.16-1 —
Debian 13 redis 5:6.0.16-1 —
Debian 12 redis 5:6.0.16-1 —
Debian 11 redis 5:6.0.16-1+deb11u1 DSA-5001-1
Debian 10 redis 5:5.0.14-1+deb10u1 DSA-5001-1
Show 1 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Debian 9 redis 3:3.2.6-3+deb9u8 DLA-2810-1

Ubuntu

Security tracker ↗
ReleasePackageFixed inAdvisory
Ubuntu Pro 20.04 LTS redis 5:5.0.7-2ubuntu0.1+esm1 USN-5221-1
Ubuntu Pro 18.04 LTS redis 5:4.0.9-1ubuntu0.2+esm3 USN-5221-1
Ubuntu Pro 16.04 LTS redis 2:3.0.6-1ubuntu0.4+esm1 USN-5221-1
Show 1 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 14.04 LTS redis 2:2.8.4-2ubuntu0.2+esm2 USN-5221-1

Red Hat

Security tracker ↗
ReleasePackageFixed inAdvisory
RHEL 8 redis +2 5.0.3-5.module+el8.4.0+12927+b9845322 RHSA-2021:3945, RHSA-2021:3918
RHEL 3 rh-redis5-redis 5.0.5-3.el7 RHSA-2021:3947
Show 4 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
RHEL 8.2 EUS redis +2 5.0.3-5.module+el8.2.0+12926+485b5fc9 RHSA-2021:3944
RHEL 8.1 EUS redis +2 5.0.3-5.module+el8.1.0+12925+6460abef RHSA-2021:3946
Red Hat OpenStack 13 redis 3.2.8-5.el7ost RHSA-2021:3980
Red Hat OpenStack 10 redis 3.2.8-5.el7ost RHSA-2021:3971

AlmaLinux

Errata ↗
ReleasePackageFixed inAdvisory
AlmaLinux 8 redis +2 5.0.3-5.module_el8.4.0+2583+b9845322 ALSA-2021:3945, ALSA-2021:3918

Rocky Linux

Errata ↗
ReleasePackageFixed inAdvisory
Rocky Linux 8 redis 5.0.3-5.module+el8.4.0+659+cf535ef1 RLSA-2021:3945, RLSA-2021:3918

SUSE

Security tracker ↗
ReleasePackageFixed inAdvisory
SLES 15 SP3 redis 6.0.14-6.8.1 SUSE-SU-2021:3772-1
SLES 15 SP2 redis 6.0.14-6.8.1 SUSE-SU-2021:3772-1

openSUSE

Security tracker ↗
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed redis 6.2.6-1.1 openSUSE-SU-2024:11563-1
openSUSE Leap 15.3 redis 6.0.14-6.8.1 openSUSE-SU-2021:3772-1

Alpine

Security tracker ↗
ReleasePackageFixed inAdvisory
Alpine v3.24 redis 6.2.6-r0 —
Alpine v3.23 redis 6.2.6-r0 —
Alpine v3.22 redis 6.2.6-r0 —
Alpine v3.21 redis 6.2.6-r0 —
Alpine v3.20 redis 6.2.6-r0 —
Show 9 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Alpine v3.19 redis 6.2.6-r0 —
Alpine v3.18 redis 6.2.6-r0 —
Alpine v3.17 redis 6.2.6-r0 —
Alpine v3.16 redis 6.2.6-r0 —
Alpine v3.15 redis 6.2.6-r0 —
Alpine v3.14 redis 6.2.6-r0 —
Alpine v3.13 redis 6.0.16-r0 —
Alpine v3.12 redis 5.0.14-r0 —
Alpine v3.11 redis 5.0.14-r0 —

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 2 (CBL-Mariner) redis 6.2.6-1 —

Oracle Linux

ReleasePackageFixed inAdvisory
Oracle Linux 8 redis +2 5.0.3-5.module+el8.4.0+20382+7694043a ELSA-2021-3945, ELSA-2021-3918

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.

GitHub 1 repository

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

Advisories 20

References