# 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.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Aug 2026
- **Updated:** 20 Aug 2026
- **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

## 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 (Use After Free)

## Which versions are affected by CVE-2026-63639?

1 open source package ship an affected version, including valkey.


| Package | Ecosystem | 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.

## Is CVE-2026-63639 being exploited?

There is no known exploitation of CVE-2026-63639 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63639 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-63639 in the wild and no public exploit code.

Affected packages and fixed versions:
- valkey (Bitnami): affected all versions; fixed in 7.2.14, 8.0.10, 8.1.9, 9.0.5, 9.1.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-63639/ (Markdown: https://insights.sbomify.com/CVE-2026-63639/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63639
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63639
- OSV: https://osv.dev/vulnerability/CVE-2026-63639

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63639/
Summaries are generated and may contain mistakes; the official description above is the record.