CVE-2026-109968
Description
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.
Statement
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.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | 5.5 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Acknowledgements
This issue was discovered by Sergio Correia (Red Hat).
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