CVE-2026-21864 Remote DoS from malformed RESTORE command
A remote attacker can crash the Valkey database server by sending a malformed RESTORE command to the Bloom module.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-21864?
CVE-2026-21864 is a medium-severity denial of service vulnerability in valkey-io valkey-bloom, published on 24 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Valkey-Bloom is a Rust based Valkey module which brings a Bloom Filter (Module) data type into the Valkey distributed key-value database. Prior to commit a68614b6e3845777d383b3a513cedcc08b3b7ccd, a specially crafted `RESTORE` command can cause Valkey to hit an assertion, causes the server to shutdown. Valkey modules are required to handle errors in RDB parsing by using `VALKEYMODULE_OPTIONS_HANDLE_IO_ERRORS` flag. If this flag is not set, errors encountered during parsing result in a system assertion which shuts down the system. Even though the Valkey-bloom module correctly handled the parsing, it did not originally set the flag. Commit a68614b6e3845777d383b3a513cedcc08b3b7ccd contains a patch. One may mitigate this defect by disabling the `RESTORE` command if it is unused by one's application.
Weakness: CWE-20
Which versions are affected by CVE-2026-21864?
It affects 1 product.
Products include Lfprojects Valkey-Bloom.
How do I fix CVE-2026-21864?
No fix has been published for CVE-2026-21864 yet. Limit exposure of the affected software until one is available.
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-2026-21864 being exploited?
There is no known exploitation of CVE-2026-21864 in the wild and no public exploit code.
Sources
Also known as GHSA-mc2g-h759-3qw2.