# CVE-2026-82677: valkey-io valkey Module Timer module.c moduleTimerHandler double free

> Remote attackers can trigger a double free in the Valkey Module Timer subsystem, potentially causing denial of service or code execution.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 31 Aug 2026
- **Updated:** 31 Aug 2026
- **Also known as:** BELL-CVE-2026-82677, DEBIAN-CVE-2026-82677, ECHO-6215-20d8-e5f2, GHSA-pjvh-64mj-595g, UBUNTU-CVE-2026-82677

## What is CVE-2026-82677?

CVE-2026-82677 is a medium-severity use after free vulnerability in valkey-io valkey, published on 31 Aug 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

A vulnerability was determined in valkey-io valkey 9.1.0. Impacted is the function moduleTimerHandler of the file src/module.c of the component Module Timer Subsystem. This manipulation causes double free. The attack can be initiated remotely. The exploit has been publicly disclosed and may be utilized. Patch name: b349fe2821e3998534b1454c1b64a478daf8c6b7. To fix this issue, it is recommended to deploy a patch.

Weakness: CWE-415 (Double Free), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-82677?


## How do I fix CVE-2026-82677?

Apply the vendor's patch.

## Is CVE-2026-82677 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82677 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82677 and fix it if it is affected.

What it is: CVE-2026-82677 is a medium-severity use after free vulnerability in valkey-io valkey, published on 31 Aug 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82677 exists.

Affected product: valkey-io valkey. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-82677/ (Markdown: https://insights.sbomify.com/CVE-2026-82677/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82677
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82677
- OSV: https://osv.dev/vulnerability/CVE-2026-82677

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82677/
Summaries are generated and may contain mistakes; the official description above is the record.