CVE-2026-109968

A flaw was found in the clevis PKCS#11 pin. The clevis-pkcs11-afunix-socket-unlock daemon logs LUKS disk encryption passphrases in plaintext to a log file. The log file is created without restrictive permissions, making it world-readable under the default process umask. A local attacker can read the log file to obtain the LUKS passphrase.

The PKCS#11 clevis pin is an opt-in feature requiring explicit configuration (clevis luks bind pkcs11), PKCS#11 hardware (smart card, HSM, YubiKey), and activation of the corresponding systemd service or dracut module. Default clevis installations are not affected.

Red Hat rates this Moderate rather than Important because exploitation requires local access to a system using the opt-in PKCS#11 pin, and the world-readable log file permissions depend on the inherited process umask rather than being hardcoded by the package. However, under the default systemd UMask of 0022, the log file is created mode 0644 (world-readable) on every boot, and the passphrase is logged unconditionally with no opt-out.

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.

Configure the clevis-luks-pkcs11-askpass systemd service with a restrictive UMask by creating a service override using systemctl edit. Setting UMask to 0077 prevents the log file from being readable by non-root users. Additionally, remove any existing log files under /run/systemd/clevis-pkcs11-*.log after each boot, as they may already contain passphrases from previous unlocks.

This workaround only covers the systemd service path. The dracut initramfs code path is not covered by this mitigation.