Crux Agent silently fails SKA preshared key rotation when SHA-512 peering is negotiated
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.
CVE-2026-107785
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-107785
Crux Agent
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"vendor": "Sirius Computer, Inc.",
"product": "Crux Agent",
"versions": [
{
"status": "affected",
"version": "1.9.0",
"lessThan": "2.0.3",
"versionType": "semver"
}
],
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-107785
Source reference:
/cveMetadata/cveId
Publisher severity
medium
Source reference: /containers/cna/metrics
- Event
- #16369 · Revision 1
- Added to Heist Feed
- Publisher date