CVE-2021-32675 DoS vulnerability in Redis
Unauthenticated attackers can cause memory exhaustion and denial of service in Redis by sending specially crafted RESP requests.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-32675?
CVE-2021-32675 is a high-severity denial of service vulnerability in Debian Debian Linux, published on 4 Oct 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-770
Which versions are affected by CVE-2021-32675?
3 open source packages ship an affected version, including keydb, redis and valkey. It affects 6 products.
| Package | Affected | Fixed in |
|---|---|---|
keydb Bitnami | From 5.0.0 | 5.0.14, 6.0.16, 6.2.6 |
redis Bitnami | From 5.0.0 | 5.0.14, 6.0.16, 6.2.6 |
valkey Bitnami | From 5.0.0 | 5.0.14, 6.0.16, 6.2.6 |
Products include Debian Debian Linux, Fedoraproject Fedora, Netapp Management Services for Element Software, Netapp Management Services for Netapp Hci, Oracle Communications Operations Monitor, Redis Redis.
How do I fix CVE-2021-32675?
Upgrade keydb to a fixed version for your release line: 5.0.14, 6.0.16 or 6.2.6.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-32675 being exploited?
There is no known exploitation of CVE-2021-32675 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as ALPINE-CVE-2021-32675, AZL-6848, BIT-keydb-2021-32675, BIT-redis-2021-32675, BIT-valkey-2021-32675, CLEANSTART-2026-PG73171 and 3 more.