TOCTOU Race Condition in boneIO

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-77059
StatePUBLISHED
AssignerCERT-PL
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-26 15:16:43 UTC
Updated2026-10-26 17:11:35 UTC
DescriptionboneIO 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.

Risk And Classification

Primary CVSS: v4.0 8.8 HIGH from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-367 | CWE-367 CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.8HIGHCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/C...
4.0CNACVSS8.8HIGHCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

CVSS v4.0 Breakdown

Attack Vector
Local
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
Low
User Interaction
None
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
High
Sub Integrity
High
Sub Availability
High

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA BoneIO BoneIO affected 1.3.0 1.6.0 semver Not specified

References

ReferenceSourceLinkTags
boneio.eu/en/docs/black [email protected] boneio.eu
cert.pl/en/posts/2026/10/CVE-2026-77052 [email protected] cert.pl
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Mateusz Włodarczak (s3ga) (en)

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