CVE-2026-63639 Valkey: UAF in stream deserialization may lead to remote code execution
A use-after-free vulnerability in Valkey's stream deserialization allows remote attackers to execute arbitrary code via a malformed RDB payload.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-63639?
CVE-2026-63639 is a high-severity use after free vulnerability in valkey-io valkey, published on 18 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Valkey is a distributed key-value database. Prior to 7.2.14, 8.0.10, 8.1.9, 9.0.5, and 9.1.1, Valkey's RESTORE command accepts a malformed RDB stream payload that assigns one Pending Entry List NACK to multiple consumers during stream consumer-group deserialization, causing a use-after-free when one consumer is deleted while another still references the shared NACK and potentially allowing remote code execution. This issue is fixed in versions 7.2.14, 8.0.10, 8.1.9, 9.0.5, and 9.1.1.
Weakness: CWE-416
Which versions are affected by CVE-2026-63639?
1 open source package ship an affected version, including valkey.
| Package | Affected | Fixed in |
|---|---|---|
valkey Bitnami | All versions | 7.2.14, 8.0.10, 8.1.9, 9.0.5, 9.1.1 |
How do I fix CVE-2026-63639?
Upgrade valkey to a fixed version for your release line: 7.2.14, 8.0.10, 8.1.9 or 9.0.5.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-63639 being exploited?
There is no known exploitation of CVE-2026-63639 in the wild and no public exploit code.
Sources
Also known as AZL-96885, BELL-CVE-2026-63639, BIT-valkey-2026-63639, DEBIAN-CVE-2026-63639, GHSA-mvcj-73cw-22m4, UBUNTU-CVE-2026-63639.