What’s Vulnerable › Vulnerabilities

CVE-2026-77059: TOCTOU Race Condition in boneIO

• Severity: high (CVSS 8.8 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-26 · updated 2026-10-26
• Weakness: CWE-367

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.

Affected products

• boneIO: from 1.3.0 before 1.6.0 — fixed in 1.6.0

How to fix

Upgrade to a fixed version: boneIO 1.6.0. Check the vendor advisory for mitigations.

References

• https://boneio.eu/en/docs/black
• https://cert.pl/en/posts/2026/10/CVE-2026-77052

Get alerted when CVE-2026-77059 or the next vulnerability affects your stack