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Fencer Vulns
high 7.5

CVE-2021-32675 in the critical feed json

DoS vulnerability in Redis

published 2021-10-04 5 y ago modified 2026-09-08 2 mo ago also BIT-keydb-2021-32675 , BIT-redis-2021-32675 , BIT-valkey-2021-32675 , EUVD-2021-19484 , GHSA-f6pw-v9gw-v64p

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
16.1%
EPSS 16.1% chance of exploitation in 30 days, percentile 96%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami keydb 5.0.14, 6.0.16, 6.2.6
  • bitnami redis 5.0.14, 6.0.16, 6.2.6
  • bitnami valkey 5.0.14, 6.0.16, 6.2.6
  • redis redis 5.0.14, 6.0.16, 6.2.6
  • redis Debian 14, Debian 13, Debian 12 5:6.0.16-1

debian advisories DEBIAN-CVE-2021-32675

  • redis Ubuntu Pro 14.04 LTS 2:2.8.4-2ubuntu0.2+esm2
  • redis Ubuntu Pro 16.04 LTS 2:3.0.6-1ubuntu0.4+esm1
  • redis Ubuntu Pro 18.04 LTS 5:4.0.9-1ubuntu0.2+esm3
  • redis Ubuntu Pro 20.04 LTS 5:5.0.7-2ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2021-32675

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

  • redis openstack 13, openstack 10 3.2.8-5.el7ost
  • rh-redis5-redis RHEL 3 SOFTWARE_COLLECTIONS 5.0.5-3.el7
  • redis RHEL 8 6.0.9-5.module+el8.4.0+12929+1bb0d2aa
  • redis RHEL 8 5.0.3-5.module+el8.4.0+12927+b9845322
  • redis RHEL 8.2 EUS 5.0.3-5.module+el8.2.0+12926+485b5fc9
  • redis RHEL 8.1 EUS 5.0.3-5.module+el8.1.0+12925+6460abef

red hat advisories RHSA-2021:3971RHSA-2021:3944RHSA-2021:3947RHSA-2021:3945RHSA-2021:3980RHSA-2021:3946

  • redis SLE Module for Server Applications 15 SP3, SLE Module for Server Applications 15 SP2 6.0.14-6.8.1

suse advisories SUSE-SU-2021:3772-1

  • redis openSUSE Tumbleweed 6.2.6-1.1
  • redis openSUSE Leap 15.3 6.0.14-6.8.1

opensuse advisories openSUSE-SU-2024:11563-1openSUSE-SU-2021:3772-1

  • redis AlmaLinux 8 6.0.9-5.module_el8.5.0+67+a3c431d9
  • redis AlmaLinux 8 6.0.9-5.module_el8.4.0+2584+1bb0d2aa
  • redis AlmaLinux 8 5.0.3-5.module_el8.4.0+2583+b9845322
  • redis AlmaLinux 8 5.0.3-5.module_el8.5.0+66+fc19ec12

almalinux advisories ALSA-2021:3945ALSA-2021:3918

  • redis Rocky Linux 8 6.0.9-5.module+el8.5.0+658+72172854
  • redis Rocky Linux 8 6.0.9-5.module+el8.4.0+660+a8447b97
  • redis Rocky Linux 8 5.0.3-5.module+el8.5.0+657+2674830e
  • redis Rocky Linux 8 5.0.3-5.module+el8.4.0+659+cf535ef1

rocky linux advisories RLSA-2021:3945RLSA-2021:3918

  • redis Alpine 3.12, Alpine 3.11 5.0.14-r0
  • redis Alpine 3.13 6.0.16-r0
  • redis Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 6.2.6-r0

alpine advisories ALPINE-CVE-2021-32675

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

  • redis CBL-Mariner 2.0 6.2.6-1

azure linux advisories AZL-6848

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2021-32675 updated cvss 7.5

redis: Denial of service via Redis Standard Protocol (RESP) request

  • Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/redisgraph-tls-rhel8
    affected: workaround, no fix available “Prevent unauthenticated users from connecting to Redis by using network access control tools (e.g., firewalls) or enabling TLS and requiring users to authenticate using client side certificates.”
  • Red Hat Enterprise Linux AppStream (v. 8) redis 5.0.3-5.module+el8.4.0+12927+b9845322, redis 6.0.9-5.module+el8.4.0+12929+1bb0d2aa
    fixed: vendor fix “Prevent unauthenticated users from connecting to Redis by using network access control tools (e.g., firewalls) or enabling TLS and requiring users to authenticate using client side certificates.” RHSA-2021:3918
  • Red Hat Enterprise Linux AppStream EUS (v. 8.1) redis 5.0.3-5.module+el8.1.0+12925+6460abef
    fixed: vendor fix “Prevent unauthenticated users from connecting to Redis by using network access control tools (e.g., firewalls) or enabling TLS and requiring users to authenticate using client side certificates.” RHSA-2021:3946
  • Red Hat Enterprise Linux AppStream EUS (v. 8.2) redis 5.0.3-5.module+el8.2.0+12926+485b5fc9
    fixed: vendor fix “Prevent unauthenticated users from connecting to Redis by using network access control tools (e.g., firewalls) or enabling TLS and requiring users to authenticate using client side certificates.” RHSA-2021:3944
  • Red Hat OpenStack Platform 10.0 redis 3.2.8-5.el7ost
    fixed: vendor fix “Prevent unauthenticated users from connecting to Redis by using network access control tools (e.g., firewalls) or enabling TLS and requiring users to authenticate using client side certificates.” RHSA-2021:3971
  • Red Hat OpenStack Platform 13.0 - ELS redis 3.2.8-5.el7ost Red Hat OpenStack Platform 13.0 for RHEL 7.6 EUS Server redis 3.2.8-5.el7ost
    fixed: vendor fix “Prevent unauthenticated users from connecting to Redis by using network access control tools (e.g., firewalls) or enabling TLS and requiring users to authenticate using client side certificates.” RHSA-2021:3980
  • Red Hat Software Collections for Red Hat Enterprise Linux Server (v. 7) rh-redis5-redis 5.0.5-3.el7 Red Hat Software Collections for Red Hat Enterprise Linux Server EUS (v. 7.7) rh-redis5-redis 5.0.5-3.el7 Red Hat Software Collections for Red Hat Enterprise Linux Workstation (v. 7) rh-redis5-redis 5.0.5-3.el7
    fixed: vendor fix “Prevent unauthenticated users from connecting to Redis by using network access control tools (e.g., firewalls) or enabling TLS and requiring users to authenticate using client side certificates.” RHSA-2021:3947
  • Red Hat 3scale API Management Platform 2 redis Red Hat Ansible Automation Platform 1.2 redis Red Hat Ansible Tower 3 redis Red Hat Enterprise Linux 9 redis Red Hat Software Collections rh-redis6-redis
    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

16.07% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/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
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami keydb
>=5.0.0, <5.0.14
>=6.0.0, <6.0.16
>=6.2.0, <6.2.6
5.0.14
6.0.16
6.2.6
bitnami redis
>=5.0.0, <5.0.14
>=6.0.0, <6.0.16
>=6.2.0, <6.2.6
5.0.14
6.0.16
6.2.6
bitnami valkey
>=5.0.0, <5.0.14
>=6.0.0, <6.0.16
>=6.2.0, <6.2.6
5.0.14
6.0.16
6.2.6

Affected products

  • redis redis

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling
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.

The maintainers of redis/redis published their own advisory on GitHub. Reviewed sources take precedence over it.