# CVE-2026-77059: TOCTOU Race Condition in boneIO


- **Severity:** High 8.8 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 26 Oct 2026
- **Updated:** 26 Oct 2026
- **Also known as:** GHSA-69w9-6j7r-c8fv

## What is CVE-2026-77059?

CVE-2026-77059 is a high-severity vulnerability in boneIO, published on 26 Oct 2026. 

### Official description

boneIO Black contains a TOCTOU race condition in the create_timedatectl_sudoers_file() function in boneio/webui/routes/timezone_sudoers.py. The function writes sudoers rules to a predictable temporary file, validates them, then installs them with root privileges. A local attacker can exploit the race window between validation and installation to substitute malicious content, or use the predictable filename for symlink attacks, resulting in arbitrary sudoers rule injection and local privilege escalation to root.

This issue was fixed in version 1.6.0.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2026-77059?


## How do I fix CVE-2026-77059?

No fix has been published for CVE-2026-77059 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-77059 being exploited?

There is no known exploitation of CVE-2026-77059 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77059 and fix it if it is affected.

What it is: CVE-2026-77059 is a high-severity vulnerability in boneIO, published on 26 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-77059 in the wild and no public exploit code.

Affected product: boneIO. 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-2026-77059/ (Markdown: https://insights.sbomify.com/CVE-2026-77059/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77059
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77059
- OSV: https://osv.dev/vulnerability/CVE-2026-77059

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-77059/
Summaries are generated and may contain mistakes; the official description above is the record.