CVE-2026-109976
Description
A flaw was found in the clevis PKCS#11 pin. The clevis-pkcs11-afunix-socket-unlock daemon crashes when an AF_UNIX client connects to the data socket without a bound address, due to an integer underflow in the getpeername result handling. This causes a denial of service, preventing LUKS disk decryption from completing during boot.
Statement
The PKCS#11 clevis pin is an opt-in feature requiring explicit configuration (clevis luks bind pkcs11), PKCS#11 hardware, and activation of the corresponding systemd service or dracut module. Default clevis installations are not affected.
Red Hat rates this Moderate because under the default systemd UMask of 0022, the data socket is created with mode 0755. AF_UNIX SOCK_STREAM requires write permission to connect, so only root can reach the vulnerable code path. Since the daemon itself runs as root, this does not cross a privilege boundary. The crash is a denial of service only — _FORTIFY_SOURCE and stack canaries independently prevent code execution.
Mitigation
No additional end-user mitigation is needed. Under the default systemd configuration, the data socket is only accessible by root, preventing unprivileged users from triggering the crash.
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 | 4.7 | N/A | 4.7 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
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