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How the CVE Works:
The vulnerability (CVE-2025-XXXXX) in `matrix-sdk-crypto` versions 0.8.0 to 0.11.0 allows a malicious homeserver administrator to spoof encrypted event senders. The flaw stems from improper validation of the `sender` field in encrypted events. While the SDK checks `room_id` and `session_id` for consistency, it fails to verify if the sender matches the trusted session. This enables a rogue admin to manipulate events, making them appear as if they originated from another user. The attack is network-based (AV:N), requires low complexity (AC:L), and demands admin privileges (PR:H), leading to high integrity impact (I:H) but no confidentiality loss (C:N).
DailyCVE Form:
Platform: Matrix-SDK-Crypto
Version: 0.8.0 – 0.11.0
Vulnerability: Sender Spoofing
Severity: Moderate
Date: Jun 10, 2025
Prediction: Patch expected by Jun 17, 2025
What Undercode Say:
Exploitation:
1. Malicious Payload:
{
"sender": "[email protected]",
"room_id": "!valid:room.id",
"session_id": "trusted_session_id"
}
2. Server-Side Manipulation:
A compromised homeserver injects events with mismatched `sender` and session_id.
3. Client Trust Exploit:
Vulnerable clients render events as legitimate due to missing sender validation.
Protection:
1. Patch Immediately:
cargo update matrix-sdk-crypto --version ">=0.11.1"
2. Manual Validation:
if event.sender != trusted_session.sender {
reject_event!();
}
3. Network Controls:
Monitor homeserver-admin activities auditd -w /var/lib/matrix -p wa -k matrix_audit
Analytics:
- Impact: High integrity risk for federated rooms.
- Detection: Log mismatched
sender–session_idpairs:if event['sender'] != session_db[event['session_id']]['sender']: alert("CVE-2025-XXXXX Exploit Attempt") - Mitigation Rate: 80% of deployments patched within 7 days (predicted).
References:
No further commentary.
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
