CVE-2026-4878

A flaw was found in libcap. A local unprivileged user can exploit a Time-of-check-to-time-of-use (TOCTOU) race condition in the cap_set_file() function. This allows an attacker with write access to a parent directory to redirect file capability updates to an attacker-controlled file. By doing so, capabilities can be injected into or stripped from unintended executables, leading to privilege escalation.

This is an Important flaw. A Time-of-Check-to-Time-of-Use (TOCTOU) race condition in libcap's cap_set_file() allows a local unprivileged user to escalate privileges. An attacker with write access to a parent directory can exploit a narrow window during file capability updates to redirect capabilities to an attacker-controlled file. This can lead to the injection of elevated privileges into an unintended executable when privileged processes, such as setcap or container tooling, invoke cap_set_file() on attacker-influenced paths.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.