CVE-2021-32675

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.

How to fix CVE-2021-32675

To remediate CVE-2021-32675, upgrade the affected package to a fixed version below.

• —upgrade to 5.0.14-r0 or later
• —upgrade to 5.0.14 or later
• —upgrade to 5.0.14 or later
• —upgrade to 5.0.14 or later
• —upgrade to 5:6.0.16-1+deb11u1 or later

Is CVE-2021-32675 being exploited?

Moderate — EPSS is 5.8%. Track this CVE but it's not at the top of the prioritisation list.

Affected packages (5)

• from 0, < 5.0.14-r0
• >= 5.0.0, < 5.0.14, >= 6.0.0, < 6.0.16, >= 6.2.0, < 6.2.6
• >= 5.0.0, < 5.0.14, >= 6.0.0, < 6.0.16, >= 6.2.0, < 6.2.6
• >= 5.0.0, < 5.0.14, >= 6.0.0, < 6.0.16, >= 6.2.0, < 6.2.6
• from 0, < 5:6.0.16-1+deb11u1

CVSS scores

References (13)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2021-32675
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2021-32675
• WEBgithub.com/redis/redis/commit/5674b0057ff2903d43eaff802017eddf37c360f8
• WEBgithub.com/redis/redis/security/advisories/GHSA-f6pw-v9gw-v64p