Vulnerability · Published Oct 26, 2026 · Assigned by CERT-PL

CVE-2026-77059TOCTOU Race Condition in boneIO

High 8.8

In plain English

A high-severity security flaw in boneIO from boneIO. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).

Severity (CVSS 4.0)8.8High

Exploit odds (30 days)0.1%top 97.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
boneIO	boneIO	1.3.0 – before 1.6.0

Weakness: CWE-367 · Vector: 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

References

https://cert.pl/en/posts/2026/10/CVE-2026-77052 third-party-advisory
https://boneio.eu/en/docs/black product