How the Vulnerability Works
CVE-2025-4166 affects Hashicorp Vault Community and Enterprise KV (Key/Value) Version 2 plugin. When users submit malformed payloads (e.g., invalid JSON or incorrect secret structures) via the Vault REST API, the server logs and audit logs may inadvertently record sensitive data. This occurs due to improper error handling, where backend processes dump raw payload contents into logs before validation completes. Attackers exploiting this flaw could retrieve secrets, tokens, or configuration details from logs, bypassing Vault’s access controls. The issue is mitigated in patched versions by sanitizing error messages and restricting log leakage.
DailyCVE Form
Platform: Hashicorp Vault
Version: < 1.19.3
Vulnerability: Information Disclosure
Severity: Moderate
Date: May 2, 2025
What Undercode Say:
Exploitation:
1. Craft Malformed Payload:
curl -X POST -H "X-Vault-Token: <token>" -d '{"malformed": "data"}' http://vault-server/v1/secret/data/path
2. Extract Logs:
grep "sensitive" /var/log/vault/audit.log
Mitigation:
1. Upgrade:
sudo apt update && sudo apt install vault=1.19.3
2. Log Sanitization:
vault.hcl disable_log_leakage = true
3. Restrict Log Access:
chmod 600 /var/log/vault/.log
Detection:
1. Audit Log Scan:
journalctl -u vault --no-pager | grep -i "error|secret"
2. API Input Validation:
Sample Flask middleware
@app.before_request
def validate_json():
try:
request.get_json()
except Exception:
return {"error": "Invalid payload"}, 400
References:
- Patch: GitHub Advisory
- NVD: CVE-2025-4166
- Vault Docs: Secure Logging
No additional commentary beyond rules.
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
