---
id: CVE-2026-107785
title: >-
  Crux Agent from 1.9.0 before 2.0.3 uses the full SKA bilocation key as the
  WireGuard preshared key
summary: >-
  Crux Agent from 1.9.0 before 2.0.3 uses the full SKA bilocation key as the
  WireGuard preshared key. When a peering session negotiates use of SHA-512, the
  key produced is 64 bytes instead of the 32 bytes WireGuard requires. The agent
  does…
severity: none
cwe:
  - CWE-252
  - CWE-325
  - CWE-394
published: '2026-10-09'
updated: '2026-10-09'
sourceUpdated: '2026-10-09T17:16:45.597'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-107785'
references:
  - url: 'https://sirius.computer/security-disclosure-policy/'
    label: d0a6edd6-4b7d-45f2-a6f9-9b944f7b6132
tags:
  - nvd
ingestedAt: '2026-10-09T15:00:31.365Z'
---

## Overview

Crux Agent from 1.9.0 before 2.0.3 uses the full SKA bilocation key as the WireGuard preshared key. When a peering session negotiates use of SHA-512, the key produced is 64 bytes instead of the 32 bytes WireGuard requires. The agent does not validate this size; instead it attempts to use the `wg set` command to update the live tunnel, and write the invalid key to the WireGuard configuration file. The update fails, so the live tunnel keeps using its previous preshared key until the tunnel is shut down. The tunnel will fail to start when restarted.



For a peer which has never successfully negotiated a 32-byte bilocation key in a Crux C2 organization which has the "Enforce SKA Use" setting turned off, no preshared key will be set for the tunnel. Therefore, an attacker who is able to intercept and store the peer's traffic, and has access (or will have access) to a cryptographically relevant quantum computer, will be able to decrypt the tunnel.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.