high
7.5
CWE
770
Advisory Published
CVE Published
Updated

CVE-2021-32675: DoS vulnerability in Redis

First published: Mon Oct 04 2021(Updated: )

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.

Credit: security-advisories@github.com

Affected SoftwareAffected VersionHow to fix
redhat/redis<0:3.2.8-5.el7
0:3.2.8-5.el7
redhat/rh-redis5-redis<0:5.0.5-3.el7
0:5.0.5-3.el7
debian/redis
5:5.0.14-1+deb10u2
5:5.0.14-1+deb10u5
5:6.0.16-1+deb11u2
5:7.0.11-1
5:7.0.14-1
redhat/redis<6.2.6
6.2.6
redhat/redis<6.0.16
6.0.16
redhat/redis<5.0.14
5.0.14
ioredis>=5.0.0<5.0.14
ioredis>=6.0.0<6.0.16
ioredis>=6.2.0<6.2.6
Fedora=33
Fedora=34
Fedora=35
Debian=10.0
Debian=11.0
NetApp Management Services for Element Software
NetApp Management Services for NetApp HCI
Oracle Communications Operations Monitor=4.3
Oracle Communications Operations Monitor=4.4
Oracle Communications Operations Monitor=5.0

Remedy

https://github.com/redis/redis/commit/5674b0057ff2903d43eaff802017eddf37c360f8

Remedy

https://lists.apache.org/thread.html/ra603ff6e04549d7f290f61f9b11e2d2e4dba693b05ff053f4ec6bc47@%3Cnotifications.geode.apache.org%3E

Remedy

https://www.oracle.com/security-alerts/cpuapr2022.html

Remedy

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.

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Reference Links

Parent vulnerabilities

(Appears in the following advisories)

Frequently Asked Questions

  • What is the vulnerability ID for this flaw in Redis?

    The vulnerability ID for this flaw in Redis is CVE-2021-32675.

  • What is Redis?

    Redis is an open source, in-memory database that persists on disk.

  • What is the severity of CVE-2021-32675?

    The severity of CVE-2021-32675 is high with a severity value of 7.5.

  • How does CVE-2021-32675 affect Redis?

    CVE-2021-32675 in Redis allows an attacker to allocate arbitrary amounts of memory, potentially leading to denial of service or remote code execution.

  • How can I fix CVE-2021-32675 in Redis?

    To fix CVE-2021-32675 in Redis, upgrade to version 6.2.6, 6.0.16, or 5.0.14 depending on your current version.

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