boneIO Black: Local privilege escalation via TOCTOU race in sudoers setup
Summary
boneIO Black home automation controllers contain a time-of-check to time-of-use race condition in the function that installs sudoers rules for timezone settings. The function writes rules to a predictable temporary file, validates them and then installs them with root privileges. A local attacker with low privileges can exploit the race window or symlink the predictable filename to inject arbitrary sudoers rules and escalate to root.
Affected
- boneIO Black, versions 1.3.0 up to but not including 1.6.0 (CNA range; the lower bound is still to be confirmed with the vendor)
Fixed in
- Fixed in boneIO 1.6.0
Workaround
- Unknown. No workaround was found in the sources. The fix is the upgrade to 1.6.0 or later.
Exploitation
- No evidence of exploitation in the wild on record.
- No public proof of concept found in the searches; this does not prove that none exists.
- CISA SSVC: Exploitation none, automatable no, technical impact total.
Our recommendation
- Upgrade all boneIO Black devices to boneIO 1.6.0 or later, together with the other boneIO CVEs published in the same batch.
- Prioritise remote, unauthenticated issues in the same batch (such as CVE-2026-77052 and CVE-2026-77053) over this local issue.
- Restrict local shell and user access to the device and restrict physical and console access until patched.
- Review /etc/sudoers.d/ for unexpected files.
- After updating, check that default or old broker credentials have been replaced.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- boneIO Black documentation boneio.eu
- CERT Polska: Vulnerabilities in boneIO products cert.pl
- OpenCVE: CVE-2026-77059 app.opencve.io
- Strix: CVE-2026-77059 www.strix.ai
- OffSeq Radar: boneIO TOCTOU race condition CVE-2026-77059 radar.offseq.com
- Vulners: CVE-2026-77059 vulners.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 10:32.
Original description (NVD)
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.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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