CVE-2026-18477

Name of the Vulnerable Software and Affected Versions GNU tar (affected versions not specified)

Description A TOCTOU (Time-of-Check Time-of-Use) issue exists in the incremental dumpdir X rename handling. This occurs when a local attacker with write access to a directory being backed up can influence the restoration process on the system where the restore is performed. During this process, files or directories may be created, renamed, or overwritten outside the intended extraction directory, potentially leading to unauthorized file modification or privilege escalation. TOCTOU is a race condition where a system checks the state of a resource before using it, but the state changes between the check and the use. This issue persists even when extracting into a new directory without the -P option.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.